Prison Labor: The Price of Prisons and the Lasting Effects of Incarceration

Abstract

Institutions of justice, like prisons, can be used to serve economic and other extrajudicial interests, with lasting deleterious effects. We study the effects on incarceration when prisoners are used primarily as a source of labor using evidence from British colonial Nigeria. We digitized sixty-five years of archival records on prisons from 1920 to 1995 and provide new estimates on the value of prison labor and the effects of labor demand shocks on incarceration. We find that prison labor was economically valuable to the colonial regime, making up a significant share of colonial public works expenditure. Positive economic shocks increased incarceration rates over the colonial period. This result is reversed in the postcolonial period, where prison labor is not a notable feature of state public finance. We document a significant reduction in contemporary trust in legal institutions, like police, in areas with high historic exposure to colonial imprisonment. The resulting reduction in trust is specific to legal institutions today.

Full text

Prison Labor: The Price of Prisons and the Lasting
Effects of Incarceration∗
Belinda Archibong†
Barnard College and NBER
Nonso Obikili‡
United Nations
August 16, 2023
Abstract
Institutions of justice, like prisons, can be used to serve economic and other extra-
judicial interests, with lasting deleterious effects. We study the effects on incarceration
when prisoners are primarily used as a source of labor using evidence from British
colonial Nigeria. We digitized 65 years of archival records on prisons from 1920 to 1995
and provide new estimates on the value of colonial prison labor and the effects of labor
demand shocks on incarceration. We find that prison labor was economically valuable
to the colonial regime, making up a significant share of colonial public works expendi-
ture. Positive economic shocks increased incarceration rates over the colonial period.
This result is reversed in the postcolonial period, where prison labor is not a notable
feature of state public finance. We document a significant reduction in present-day
trust in legal institutions, such as the police, in areas with high historical exposure to
colonial imprisonment; the resulting reduction in trust is specific to legal institutions.
JEL classification: H5, J47, O10, O43, N37
Keywords: Prison, Incarceration, Tax, Convict Labor, Colonialism, Trust
∗Thanks to Stelios Michalopoulos, Nathan Nunn, James Fenske, James Robinson, Liz Ananat, Ebonya
Washington, Eduardo Montero, Nancy Qian, David Weiman, Marlous van Waijenburg, Suresh Naidu, Warren
Whatley, Lee Alston, Leonard Wantchekon, Michiel de Haas, Denis Cogneau, Rajiv Sethi, Ewout Frankema,
Florence Bernault, Naomi Lamoreaux, Gerald Jaynes, Tim Guinnane, Robynn Cox, Peter Henry, Marcellus
Andrews, Claudia Goldin, Owen Ozier, Bryce Steinberg, Ellora Derenoncourt, Christopher Muller, Larry
Katz, anonymous referees, and participants at the NBER and BREAD meetings, the Harvard, Yale, Duke,
Brown, UC Berkeley, Columbia, Queens College, Tennessee, Williams, University of Michigan, Stanford, Ox-
ford and PSE seminars, the SSHA, LACEHA, AEHN, ASA, AEA and other conferences for useful comments
and suggestions. Thanks to Yuusuf Caruso, Monique Harmon, Anamaria Lopez, Robrenisha Williams, Chloe
Dennison, and Serena Lewis for excellent research assistance. All errors are our own.
†Corresponding author. Barnard College, Columbia University. 3009 Broadway, New York, NY 10027,
USA, and NBER. ba2207@columbia.edu.
‡me@nonsoobikili.com. The views expressed here are the authors’ and not necessarily those of the UN.
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1 Introduction
Across Europe’s African colonies, prisons were viewed as a legally sanctioned means of ad-
dressing chronic labor shortages and minimizing the costs associated with hiring wage labor
to construct and maintain public infrastructure like the railroad and roads. Unlike other
parts of colonial administration which were often characterized by indirect rule, where local
officials exerted significance influence over economic extraction activities like tax collection
from local populations, colonial prisons were administered directly by colonial officials who
maintained detailed records on the use of prison labor, exemplified by the below quote from
Inspector Jackson in Nigeria (Archibong, 2019; Lowes and Montero, 2021a).
“The Prison at Port Harcourt has been considerably developed and at the close
of the year there were 829 prisoners in custody and these are employed by the
Eastern Railway. The Engineer in charge at Port Harcourt is highly pleased with
the way the prisoners are worked; they have given no trouble and have been of
great assistance in developing that station. It was my intention to have 1,000
prisoners stationed there before the close of the year, but this was impossible as
two prisons...which should have supplied the drafts to make up the number, had
an outbreak of chicken-pox...”
- E. Jackson, Acting Inspector of Prisons, Lagos, April 23, 1915
These records provide a window into the economics of colonial extraction using formal
legal institutions. The historical evidence allows us to answer important questions on the
economics of colonial institutions, including why and how prison labor was so valuable to
the colonial regime, the incentives for incarceration that arose from colonial governments
viewing African prisoners primarily as a reserve of labor, and the long-term effects of the
colonial prison labor system on populations’ views of state legitimacy and contemporary trust
in legal institutions. They also provide important contrasting evidence to the hypothesis
that European colonizers, focused on extraction, established weak institutions to enable
this extraction, and that strong institutions, centered on laws protecting property rights,
led to positive long-run development outcomes (Acemoglu and Robinson, 2001; Dell and
Olken, 2020). The evidence from colonial prison labor institutions in Africa illustrates that a
complex, formal system of prisons, laws, courts and police was crucial for economic extraction
in Europe’s African colonies, with negative short-run and long-run consequences for local
African populations. The case of colonial prison labor highlights an important insight on the
development effects of colonial institutions- that the implementation of these institutions,
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not just whether or not they were “inclusive” or “extractive”, was important for determining
their impacts on economic development.
We study the economics of colonial prison labor and its long-run effects on African de-
velopment using evidence from British colonial Nigeria, covering a period between 1920 and
19591, when prison labor was a feature of state public finance and administration; and from
postcolonial Nigeria, covering a period between 1971 and 1995, when prison labor was not a
major feature of state finance. We construct a novel dataset from 65 years of archival records
on prisons from 1920 to 1995, assembling data on prisons, wages, prices, and colonial public
finance from colonial and postcolonial archives, along with geocoded climate information
from high-resolution NASA data to test our hypotheses. Our new dataset represents one of
the most comprehensive records on the economics of colonial prison labor and incarceration
in Africa, spanning both the colonial and postcolonial periods. Colonial Nigeria is an in-
formative region in which to study these issues for a number of reasons. Notably, colonial
Nigeria had relatively high incarceration rates. As of 1940, the British colonial government
in Nigeria was incarcerating more people (0.3%-0.4%) than the United States (0.1%) and
countries in Europe over a similar period (0.06% in 1950) (Muller, 2021; Jacobson, Heard,
and Fair, 2017). To put these figures in context with contemporary data, Figure 1 presents
the top 40 of 222 countries/jurisdictions in the world as of 2018 by incarceration rate. If
we place colonial Nigeria’s incarceration rate in 1940 on the chart, it would have ranked at
number 15 of 222 in 2018, right between the Seychelles and Panama. Nigeria incarcerates a
much lower share of people currently, ranking at around 211 of 222 by World Prison Brief
estimates.
We conduct our analysis in three steps. First, to understand why prison labor was so
valuable to the colonial regime, we calculate the value of unpaid prison labor, and estimate
the share of prison labor in colonial public finance. A key insight from the historical archives
is that prison labor on government public works was a mandated aspect of incarceration, as
part of explicit colonial policy, and prisoners were not paid a wage for their labor.2Unpaid
prison labor was a key input in the construction and maintenance of essential revenue-
generating public works, such as the railroad, which was used to transport agricultural
commodities for export. We estimate the value of unpaid wages to prisoners or unpaid
1Nigeria as an amalgamated entity was a British colony from 1914 to 1960; hence, our dataset covers
almost 40 of the 47 years of the colonial period. The country was under military rule for most of 1960 to
1999, before transitioning to democracy in 1999.
2The 1916 Prison Ordinance explicitly outlined the use of convict labor explicitly (Kingdon, 1923).
3

prison labor and show that it was economically valuable to the colonial regime. The overall
gross value of prison labor was strictly positive over the entire colonial period. Even after
accounting for the most expansive set of prisoner maintenance costs, the net value of prison
labor was nonnegative in 60% of the years from 1920 to 1959 in Nigeria. On average, the gross
value of prison labor was more than double the amount spent by the colonial government on
public works between 1920 and 1959.
Second, we show that, faced with labor shortages and aiming to minimize the costs
of administration, the colonial regime used prison labor to address their economic needs.
Chronic labor shortages were an endemic feature of the labor market in colonial Africa
due to the joint factors of high land to labor ratios, rising demand for labor for colonial
construction and subsequent relatively high prices of labor (van Waijenburg, 2018). Historical
evidence suggests that incarceration rates increased when there was a shortfall of labor for
construction and maintenance of public works; this was particularly true during periods
of positive agricultural productivity shocks, when agricultural wages increased and wage
labor was relatively more costly to attain (Abiodun, 2017; Bernault, 2007). Labor shortages
and tight labor markets, worsened by wage ceilings in the government public works sector,
increased the demand for unpaid prison labor, in line with predictions from theoretical models
of labor coercion (Acemoglu and Wolitzky, 2011). One way colonial authorities addressed
these labor shortages was to increase the number of incarcerated individuals by, for instance,
increasing prosecutions of minor, misdemeanor crimes, and switching the punishment of
these crimes from fines to imprisonment (Killingray, 1999). The use of prison labor continued
through the end of the colonial period in 1960. After independence, prison labor become less
important for the regime. The discovery of oil in 1956 and an oil price boom in the 1970s,
along with increased protests from labor unions, led to a steep decline in the use of prison
labor in postcolonial Nigeria (Abiodun, 2017).
We quantitatively test these historical accounts of the effects of labor demand shocks
on incarceration and the use of colonial prison labor by estimating the effects of shocks to
economic productivity on incarceration rates using a panel regression framework. We con-
struct two measures of shocks to economic productivity. The first measure uses agricultural
commodity export prices and district-level crop suitability, and the second measure exploits
district-level rainfall deviations in a primarily agricultural setting. We show that the in-
carceration rate is procyclical during the colonial period. Positive economic shocks increase
the colonial incarceration rate and the use of prison labor. The positive effect is specific to
the short-term incarceration rate only, with shocks increasing the share of prisoners with
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short sentences of fewer than six months. There is no effect on incarceration of prisoners
with sentences longer than two years. Using an index of export crop prices, we show that a
10% increase in export prices for a major cash crop in producing regions is associated with
a 5% increase in short-term incarceration relative to the sample mean. In a second spec-
ification, moderate positive rainfall shocks that raised agricultural productivity, increased
the short-term incarceration rate by 16.7 prisoners per 100,000 people, representing a 12%
increase relative to a mean of 134.7. This effect is reversed in the postcolonial period wherein
prison labor is not a main feature of state policy, and negative productivity shocks increase
the incarceration rate. The results provide support to the qualitative historical evidence
on the use of prison labor to address labor shortages in the colonial period, but not in the
postcolonial period.
To provide further evidence on the mechanisms driving the colonial incarceration re-
sults, we test the tight labor market hypothesis by examining the effects of rising wages on
the rate of incarceration and how this varied depending on a prison’s distance to the colonial
railroad. The rationale here is that since a major use of prison labor was for the construction
and maintenance of the railroad, examining the correlation between wages and incarceration
rates at prisons around the railroad can provide insights into how demand for colonial prison
labor changed during periods of higher wages. While short-term sentenced prisoners near the
railroad were generally used as a reserve of unpaid labor for railroad construction and main-
tenance, rising wages intensified the demand for unpaid prison labor. To increase the use
of prison labor, colonial officials would need to increase the numbers of prisoners in prisons
farther away from the railroad as well, since prisons farther away from the railroad generally
had fewer prisoners, on average, than those closer to the railroad. In other words, prisons
that were located farther away from the railroad potentially had more space to respond to
increased demand for prisoners since they generally had fewer prisoners than prisons close
to the railroad. Prisoners, by law, could not be transferred across districts, but could be
transferred from one prison to another within the same district (Foreign and Office, 1947).
Colonial officials could then transport prisoners within the colonial district to conduct work
on the railroad and associated public works as needed during periods of labor shortages
and tight labor markets. The results show that when wages increased, prisons farther away
from the railroad but within the same district, experienced an increase in the number of
prisoners incarcerated for short-term sentences. We also provide suggestive evidence of the
sentence-switching channel, and show that increasing the prison sentences of prisoners that
were already incarcerated may be one way that colonial officials intensified the use of prison
5

labor in response to labor demand shocks.
Finally, in the third step of our analysis, we study the long-run effects of colonial
use of prison labor on present-day trust in legal institutions. The judicial system in colonial
Nigeria was highly centralized, with the colonial courts working in concert with prison officials
and police to “maintain law and order”, protect European property, and meet the revenue
objectives of the colonial government under the prison labor system (Rotimi, 1993; Onoge,
1993). The police were often the first point of contact with the judicial system for local
populations and were especially involved in enforcing tax collection, including tax raids and
arrests associated with violations of colonial crimes. They were also notoriously feared for
their frequent use of violence against local populations. Much of the administrative structure
of the judicial system remained in place through the postcolonial period. Since the origins
of the modern prison and accompanying legal system in Nigeria and other former British
colonies are rooted in the use of state policy around labor coercion, what are the long-
term effects, if any, of exposure to these systems on populations’ trust in these institutions?
We use Afrobarometer data on trust in historical legal institutions in Nigeria (e.g., police,
courts, and tax administration) to examine whether past exposure to coercive, ostensibly
economically influenced, colonial prison systems is associated with current trust in legal
institutions. We document a significant reduction in contemporary trust in legal institutions,
and police, in particular, in areas with high historic exposure to colonial imprisonment. The
resulting reduction in trust is specific to legal institutions, with no evident effect of colonial
imprisonment on interpersonal trust in individuals.
We add to several literatures and debates on the effects of historic, particularly colonial
era, institutions on economic development (Lowes and Montero, 2021a; Dell and Olken, 2020;
Michalopoulos and Papaioannou, 2016, 2014; Acemoglu and Robinson, 2001). Our paper
illustrates that “inclusive”, strong formal institutions and laws can be implemented in ways
that actually reduce economic returns to local populations in the short-run, through their
incarceration and use for unpaid labor, and weaken contemporary institutions in the long-
run by lowering trust in the judicial system. While previous work has examined the long-run
impacts of institutions like the slave trade (Nunn, 2008), colonial labor concessions (Dell,
2010; Lowes and Montero, 2021a; Dell and Olken, 2020) and health (Lowes and Montero,
2021b; Alsan and Wanamaker, 2018) on development outcomes, interpersonal trust (Nunn
and Wantchekon, 2011; Okoye, 2021) and trust in modern medicine (Lowes and Montero,
2021b; Alsan and Wanamaker, 2018), our paper breaks new ground by exploring the incentive
effects of colonial prison labor systems and their long-term impacts on societal trust in legal
6

institutions. This kind of exploration is needed, particularly in light of research linking
environments of low trust in legal institutions and low views of state legitimacy with conflict
(Rohner, Thoenig, and Zilibotti, 2013), low domestic investment and higher transaction costs
from weak contract enforcement (Knack and Keefer, 1997), as well as issues such as effective
policing, crime, and law enforcement (O’Flaherty and Sethi, 2019).
We also add to the literature on the economics of forced labor and coercive labor
contracts (Acemoglu and Wolitzky, 2011; Bobonis and Morrow, 2014; Dell, 2010; Gregory and
Lazarev, 2013; Juif and Frankema, 2018; Lowes and Montero, 2021a; Naidu and Yuchtman,
2013; van Waijenburg, 2018; Saleh, 2019; Dippel, Greif, and Trefler, 2020; Sokoloff and
Engerman, 2000). Research in this area has examined the impacts of economic shocks on
coercive contract enforcement (Naidu and Yuchtman, 2013), and estimated the share of
forced labor in colonial public finance (van Waijenburg, 2018). However, there is very little
evidence on the economics of prison labor. Most research on convict labor is concentrated
on the United States and focused on the institution of convict leasing in the 19th century
when Black-Americans, in particular, were economically exploited by the US government,
in concert with private employers, for their labor (Muller, 2018, 2021; Poyker, 2019; Travis,
Western, and Redburn, 2014; Cox, 2010). A key difference between the US convict leasing
system and the use of prison labor in British colonial Nigeria, is that while, prisoners were
primarily used by private employers in the US, prison labor in British colonial Nigeria was
mainly used by government employers, with different resulting implications for the effects
of labor demand shocks on incarceration rates across the two systems (Muller, 2018, 2021;
Poyker, 2019).3Relatedly, we add to the literature on the economics of incarceration (Becker,
1968; Avio, 1998; Katz, Levitt, and Shustorovich, 2003). While previous work has focused
on the effects of crime and prison conditions on incarceration rates and recidivism (Becker,
1968; Freeman, 1999; Bhuller et al., 2020; Katz, Levitt, and Shustorovich, 2003), we highlight
the role of economic shocks in increasing incarceration under coercive state institutions.
The paper is organized as follows: Section 2 provides historical background on prison
labor in colonial Africa. Section 3 reports quantitative estimates of the value of prison labor
to the colonial regime. Section 4 describes the data on incarceration and economic shocks,
3While similar systems of coercive laws, courts and policing worked to coerce Black labor in the US and
Nigeria, the differences in the uses of prison labor led to varying implications for the effects of labor demand
shocks. White private sector employers were able to both affect incarceration rates and draw on imprisoned
Black populations under the US system, in ways that they could not under the British colonial system,
leading to sometimes opposite effects of labor demand shocks on incarceration and the demand for convict
labor across the two systems (Muller, 2018, 2021).
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and presents the results on the effects of economic shocks on the incarceration rate and
the use of prison labor. Section 5 discusses the links between colonial imprisonment and
contemporary trust in legal institutions. Section 6 concludes.
2 Prison Labor in Colonial Africa
2.1 A History of Forced Labor
Prison labor was a small aspect of a larger regime of domestic forced labor in colonial Africa.
European colonial governments were tasked with pursuing strategies to maximize revenue
while minimizing the cost of administration in Africa (Gardner, 2012). Attempts to raise
revenue to fund expenditures on key public works projects, such as roads and railroads,
which were necessary for both revenue extraction from cash crop exports and expansion of
colonial control, depended crucially on the colonial government’s ability to raise revenue
through direct or indirect taxation, and cut costs associated with spending on capital and
labor. Labor shortages were an endemic feature of African colonies (Okia, 2012; Ash, 2006).
Shortages were partly driven by an unattractive wage labor market for government projects,
which itself was partly spurred by artificially imposed below market wage compensation, set
both as a cost-cutting measure and to prevent competition with the private sector4(Okia,
2012; Maul, 2007; Ofonagoro, 1982).
European colonialists were particularly concerned with the “Africa labor question,”
wherein, faced with the joint realities of labor shortages and colonial objectives to minimize
labor costs and maximize revenues, colonial administrators questioned how much coercion a
“civilized government” could use to attain labor (Cooper, 1996; Buell, 1965). After numerous
colonial forced labor scandals,5the Forced Labor Convention at the 1930 International Labor
Organization (ILO) conference was passed. The Forced Labor Convention prohibited the
use of forced labor for private industry, defining forced labor as “all work or service which is
extracted from any person under the menace of any penalty and for which the said person has
not offered himself voluntarily” (Cooper, 1996).6Crucially, the Convention made exceptions
for the use of forced labor for public works, “penal and communal labor in the public sector
and compulsory military service” (Kunkel, 2018; Killingray, 1989).
4And also to satisfy the economic and political demands of white settler employers in colonies like Kenya
(Okia, 2012).
5Most infamous of which was the torture and murder of millions of Congolese for the rubber extraction
trade under Belgium’s King Leopold (Lowes and Montero, 2021a).
6ILO 29, Article 2 s 2a, c, e, Articles 4 and 5
8

The answer to European colonial administrators’ “Africa labor question” involved the
institution of various coercive labor regimes, enforced by legislation and through the partic-
ipation of local chiefs or Native Administrators. Among these strategies included the use of
direct taxation, such as hut and poll taxes requiring cash payment, to induce Africans into
the colonial wage labor market; the use of labor tax legislation to force Africans to donate
a certain number of hours of often unpaid labor to private and public sector work; and the
use of precolonial communal labor requirements to compel Africans, under the direction of
the chiefs, to provide unpaid labor for private and public works projects (Okia, 2012; Harris,
1914; Trevor, 1936; van Waijenburg, 2018; Cooper, 1996). The consequences for flouting
such legislation were often fines and imprisonment (Okia, 2012). Another important source
of forced labor for the colonial public sector, sanctioned by the ILO Forced Labor Convention,
was convicts (Hynd, 2015; Bernault, 2007).
2.2 The Prison System in British Colonial Nigeria
Prison was not a main feature of judicial punishment prior to colonial rule across much of
Africa (Bernault, 2007).7In British colonial Nigeria, which lasted formally from 1914 to
19608, labor taxes and labor laws worked in concert with Masters and Servants Ordinances,
vagrancy laws, labor registration, pass laws, and Native Authority Ordinances that mandated
the exploitation of African laborers to work on colonial public works projects (Hynd, 2015).9
There was also military conscription, with Africans conscripted as laborers for wartime
construction and general non-combatant labor (Killingray, 1989).10
As previously noted, the consequences for flouting this legislation often included fines
and imprisonment. The goal of the prison system, codified in colonial law with the 1916
Prisons Ordinance, was twofold. First, prisoners worked as punishment for crimes, as defined
by the colonial government; and second, unpaid prisoners were viewed as a source of cheap
labor, particularly for work on public infrastructure projects in the colonies (Adamson, 1984).
In Nigeria, by law, prisoners were only allowed to work for government agencies in the public
sector and not for private sector employers (Kingdon, 1923; Abiodun, 2017; Foreign and
7The popular punishment for transgressions within communities included ridicule ceremonies, community
sanction and exile in the most severe cases (Bernault, 2007; Onoge, 1993).
8Although the British colonial presence in the region dated back to 1860 (Archibong, 2019).
9These laws were widely used throughout colonial Africa, and were very similar to the Black Codes used
to coerce African-American labor in the US in the 19th century (Adamson, 1984).
10Forced labor for military service was permitted under the ILO Forced Labor Convention and also used
extensively during wartime. A notable instance of the use of this labor was during World War II where
thousands of Africans were conscripted to work on various tasks like porters, builders and cleaners, for the
British colonial government (Killingray, 1986).
9

Office, 1947).11 Additionally, prisoners could not be transported across long distances and
were legally bound to work only within their provincial districts (Foreign and Office, 1947).
Under the 1916 ordinance, Nigeria’s colonial prison system was initially administered
as a dual system, with colonial prisons under the direct supervision of colonial government
officials and the management of the Director of Prisons, and Native Authority prisons di-
rectly overseen by the local chiefs and indirectly supervised by colonial government officials
(Kingdon, 1923).12 Figure 2 presents the distribution of colonial prisons, provinces and
regions in Nigeria along with the distribution of the colonial railroad. The colonial rail-
road was primarily constructed between 1900 and 1930, and was functional only through
the end of the colonial period (Okoye, Pongou, and Yokossi, 2019). The railroad, like the
road networks and other colonial public works infrastructure, was largely used to transport
agricultural commodities and mineral resources to the coast for export. Prisoners made up
a substantial part of the labor on colonial public works like the railroad, and prisons were
frequently located along key public works infrastructure like the railroad, as shown in Fig-
ure 2, to minimize costs of transportation, and adhere to the 1916 Ordinance prohibiting
transport of prisoners across provinces (Ekechi, 1989; Foreign and Office, 1960).13 Under the
1916 Order in Council Act, colonial prisons were strictly classified into three types based on
lengths of prison sentence, including convict prisons, with prisoners serving two or more years
to life sentences; provincial prisons, with prisoners serving greater than six months and less
than two-year sentences; and divisional prisons, with prisoners serving less than or equal to
six-month sentences (Kingdon, 1923; Abiodun, 2017). Most prisoners had shorter sentences
of fewer than two years, with 65%-90% of convicts in provincial or divisional prisons (Hynd,
2015).
2.3 Labor Shortages, Public Works and Prison Labor
To address chronic labor shortages and minimize the costs associated with hiring wage labor
to construct and maintain public works like the railroad and roads, colonial governments
regularly used prisoners for labor. Prisoners in colonial Nigeria worked almost entirely on
11This is unlike in another well-known prison labor system, the US convict leasing system in the 19th
century where prisoners were leased to private companies (Muller, 2018).
12There is little historical information on the functioning of the Native Authority prisons, and we refer
to records on colonial prisons in this study. This means the number of colonial prisoners presented here
represent only a fraction of the total number of individuals imprisoned during this period. We discuss this
further in Section 3 and in Appendix A.2. Prisons were also administered by northern and southern regions,
and further detail on this is also provided in Appendix A.2.
13This strategic placement of prisons and prisoners around key infrastructure like the railway is highlighted
in the opening quote from Inspector Jackson.
10

public works projects (Hynd, 2015; Bernault, 2007). In Nigeria, by law, all able-bodied
prisoners were mandated to work, and only prisoners who had been sentenced could work
(Report, 1925).14 Additionally, prisoners were completely unpaid for their labor. Particularly
during periods of labor shortages, prison departments would hire out unpaid prison labor to
other colonial government departments. These departments would then pay a small fee to
the Prisons department based on the assessed skill needed from the prisoner.
Prisoners were largely engaged in unskilled labor, and prison departments classified
prisoners’ labor into three categories of unskilled hard labor, skilled hard labor (sometimes
referred to as industrial labor), and light or domestic labor.15 Unskilled hard labor included
tasks like quarrying, breaking rocks, felling trees, and other activities for road-making and
railway station upkeep, and was largely assigned to prisoners with short-term sentences of
less than six months. Skilled hard labor included tasks like basket-weaving, brick-making,
tailoring and carpentry, and was usually assigned to prisoners with long-term sentences of
greater than two years.16 Light labor was frequently assigned to sick or old prisoners, or
the 6% of female prisoners within the colonial prison system. In southern Nigeria, between
73% and 91% of prisoners were engaged in either hard or light labor between 1920 and
1938.17 Prisoners engaged in hard labor alone constituted over 70% of convicts over the
same period. The top consumers of this unpaid prison labor were government departments,
including Public Works, Railways and Harbors, Public Health, and Education (Hynd, 2015;
Report, 1925).
Prison labor, sourced primarily from prisoners with short-term sentences who made up
the vast majority of the prison population (76% of sentenced prisoners in Nigeria between
1920 and 1938), was invaluable to the construction of colonial public works and infrastruc-
ture18. Their labor significantly contributed to public works projects such as quarries and
14Between 9% and 26% of prisoners were considered “unfit” for work either due to being non-sentenced
debtors, not yet sentenced individuals in custody awaiting trial, or being too sick to work. Source: British
Blue Books, Nigeria, multiple years.
15Source: Annual Report on Prisons in Nigeria, 1940.
16The rationale provided by colonial prison officials was that these prisoners could be taught a skill given
their long sentences, whereas, prisoners with short-term sentences would not have enough time to learn a
skill. Prisoners in this skilled hard labor category produced items like uniforms that were then sold to other
government departments for profit. Prison labor was reserved exclusively for government use, and colonial
officials were careful to choose sectors for convict labor in order to avoid competing with private industries.
Source: Annual report on the Treatment of Offenders, 1947, British Blue Books and Annual Report on
Prisons, 1920-1959
17Source: British colonial Blue Books, multiple years.
18A regular section in the colonial prison reports highlighted the value of prison labor as shown in Figure
A2 in the Appendix.
11

coalfields in southern Nigeria; the Eastern Railway extending from Port-Harcourt in Owerri
province was constructed using large gangs of prison labor, and prisoners engaged in station
upkeep worked across southeastern Nigeria through the 1950s (Hynd, 2015; Ekechi, 1989;
Abiodun, 2017; Foreign and Office, 1960). Prisoner maintenance costs included expenditures
to feed, clothe and house prisoners, the costs of prison staff salaries, and all other expendi-
ture involved in operating the prisons. Tight labor markets worsened labor shortages, and
periods of higher average annual wages were positively correlated with a larger daily number
of people in prisons as shown in Figure 3.19
The recruitment of prisoners to address labor shortages was also explicitly acknowl-
edged by colonial officials. In one infamous account, a British sanitary inspector wrote to
colonial government officials to request increased funds to employ more wage labor. The
officials denied his request, and “The officials asked the prison department to find ways to
either increase the prison population or recruit convicts from outstation prisons to complete
the tasks”.20 In another example, in the 1916 Annual Report on Prisons, the Inspector of
Prisons, W.H. Beverley, lists two main reasons for creating categories of prisons according
to prison sentence:
“(a) to place ‘special prisons’ in townships which are on good lines of commu-
nication and afford the most suitable description of penal labour. (Abeokuta,
Enugu, Lagos, and Port Harcourt, on the eastern and western lines of the Nige-
rian Railway, provide quarrying, industrial work, labour connected with shipping
and transport, etc.)” and (b) “the ensuring, as far as possible, of an automatic
and constant supply of prisoners to each class of prisons. At the end of the
year, the system appeared to be working well; the prison population was evenly
distributed, and nowhere was there shortage of convict labour.”
So significant was the role of prison labor in colonial fiscal accounting, that in 1911,
the Governor of Northern Nigeria remarked that “The value (calculated at 2/3 of the market
rate) of prisoners’ labor in connection with public works, which would otherwise have had
to be paid for in cash was 3,878 pounds. If calculated at the ordinary market rates the value
of the prisoners’ useful labor would have exceeded the entire cost of the Prison Department”
(Salau, 2015). The use of prison labor to address labor shortages in the public works sector
19The correlation between the daily average numbers in prison and the average annual wage to unskilled
laborers is 0.87, p < .001. We discuss these trends in detail in Section 3.
20NAI, CSO 26/2 09591 Vol.1 ‘Lieutenant Governor Southern Province to Resident Calabar Province:
Memorandum on Prison labor’ 23rd April 1923.
12

continued through the end of the colonial period. By the year of independence in 1960, both
incarceration rates and the use of prison labor had diminished, as shown in Figure 4. As of
1938, 0.2% of the local population was incarcerated; that share had fallen to 0.06% of the
population by 1995. While the laws allowing prison labor for government use remained in
place through the postcolonial period,21 the discovery of oil in 1956, followed by an oil price
boom in the 1970s, altered Nigeria’s tax revenue structure, and the majority of government
revenue transitioned from the agricultural commodities of the colonial period to direct taxes
from petroleum.22 . With the transformation to a capital-intensive oil revenue base, the need
for a large base of unskilled labor for public works construction and maintenance with the
goal of agricultural commodity extraction declined in the postcolonial period. This change
in the government revenue base, along with increased protests from labor unions, led to a
decline in the use of prison labor in postcolonial Nigeria (Killingray, 1999; Abiodun, 2017).
2.4 Crime and Punishment
Although there is limited disaggregated data on the types of crimes individuals were con-
victed of during the colonial period, available data from colonial records in Nigeria show
that, on average, 61% of total convictions in colonial courts were from “offences against
revenue laws, municipal, road and other laws relating to social economy of the colony” be-
tween 1920 and 1939, as shown in Figure 5.23 These offenses included defaulting on tax
payments, and violations of vagrancy, labor ordinance, township ordinance (which restricted
the movement of Africans in the provinces), and other similar, minor, “misdemeanor” laws.24
Combined with “miscellaneous minor offences” which included crimes like “drunk and disor-
derly”, “witchcraft,” and other crimes against “public morality”, these minor misdemeanor
offenses accounted for 76% of colonial court convictions between 1920 and 1939. Fines were
most frequently assigned as the main punishment for these misdemeanor crimes, with im-
prisonment sometimes assigned as punishment, or assigned for individuals who were unable
to pay the fines, at the discretion of the colonial court magistrate (Hynd, 2015). An impor-
21Prison labor was never completely abolished as a feature of imprisonment in Nigeria, and prison labor as
mandated by constitutions in Nigeria since independence (e.g., the 1979 and 1999 constitutions), continues
to be a feature in prison (Shajobi-Ibikunle, 2014). More recent constitutional changes have implemented
stricter mandates regarding the work of prisoners, in many cases, limiting work to within the prisons, with
more rhetoric around the rehabilitation and reformation of prisoners under The Nigerian Prisons Service and
Article 9 of the 1972 Prison Act (Tanimu, 2010).
22As shown in Figure A1 in the Appendix.
23Source: British colonial Blue Books, multiple years. There are no disaggregated crime data by the
categories listed in the colonial records between 1940 and 1960.
24Source: “Policing in Lagos and Provinces, 1899-1929”. Reference: 73242C-01; “Judicial and Police,
1899-1960”, British Foreign and Commonwealth Office.
13

tant lever for colonial governments seeking to increase the prison labor base was to increase
prosecutions of the aforementioned minor offenses, and switch punishments from fines to im-
prisonment (Hynd, 2015; Ojomo and Alemika, 1993). In contrast, in the postcolonial period,
when prison labor was no longer used intensively by governments, a major share of crimes
(46%, on average, between 1977 and 1993) prosecuted for incarceration were for property
theft (Figure 5).
2.5 Policing and Enforcement
The judicial system in colonial Nigeria was highly centralized, with the colonial courts work-
ing in concert with prison officials and police to “maintain law and order”, protect European
property, and meet the revenue imperative objectives of the colonial government25 (Rotimi,
1993; Onoge, 1993). The colonial police force was headed by colonial officials, with rank
and file constables, constituting the majority of the base, recruited from local populations
across the country.26 The police were often the first point of contact with the judicial system
for local populations and were especially involved in enforcing tax collection and frequently
involved in tax raids and arrests associated with violations of colonial crimes (Rotimi, 1993;
Onoge, 1993). The police were notoriously feared for their frequent use of violence against
local populations.27 The 1930s witnessed multiple public protests against police brutality.
One infamous protest against the use of police in tax collection, included reports from ob-
servers like a local reverend commenting on being horrified by the sight of women “hunted
down and dragged about on public streets” by police for defaulting on tax payment (Rotimi,
1993). Much of the administrative structure of the police force remained in place through the
postcolonial period. The police in Nigeria, and across much of colonial Africa, where similar
systems were implemented, remain a national body, and there have been multiple critiques
from scholars highlighting “tremendous continuity in the country’s policing traditions and
goals in spite of a series of organizational reforms” (Ojomo and Alemika, 1993; Sanny and
25The colonial police was administered under 2 separate, but jointly legislated forces in northern and
southern Nigeria and amalgamated into a national police force in 1930.
26A popular strategy of colonial officials was to divide police from local populations by hiring rank and file
officers from separate ethnic regions of the country. The strategy was elaborated by colonial official Freeman
in a letter to the Duke of Newcastle in December 1863, wherein he argued that raising a police force for
Lagos (which had a majority Yoruba ethnic population) from mainly Hausas would make it difficult for a
rapport to develop between the police and the people of Lagos against whom they were to enforce repressive
laws (Ojomo and Alemika, 1993).
27Colonial police fear as a feature of local memory is reflected in local songs like the ones from the Urhobo
ethnic group recalling the humiliation of men who fell victim to police ambush during tax raids and were
subsequently locked up in police cells. The songs crystallized colonial policemen as ‘terroristic bogeys’ in
local communities (Onoge, 1993).
14

Logan, 2020). These critiques have also linked continuity in coercive policing practices to
relatively high levels of mistrust in police in these regions today (Sanny and Logan, 2020).
3 Estimating the Value of Prison Labor
The qualitative accounts from colonial records, described in Section 2, highlight the value
of prison labor in Nigeria. To understand why prison labor was so valuable to the colonial
regime, we quantitatively estimate the value of unpaid prison labor. In essence, we ask, “how
much would the colonial state have had to pay if they had to hire non-remunerated prison
workers for a market rate wage?” To assess this value of unpaid prison labor, we digitized
archival records on prison populations, wages, public works expenditure, and revenue from
the British colonial Blue Books and Annual Report on the Administration of the Prisons
Department28 between 1920 and 1959. The Blue Books present statistical returns that
governors of British dependencies were required to submit on an annual basis and report a
complete record of prisons and colonial public finance in Nigeria between 1920 and 1959.29
The Blue Books and the Annual Report also include qualitative descriptions of the activities
undertaken by prison departments, as reported by the Director of Prisons30. These data
sources and the variables we use in our analysis are described in detail in Appendix A.1. As
noted in Section 2.2, the colonial prisons data represent only a fraction of the overall prison
population in Nigeria.31 The results from this analysis provide us with an estimate of the
size of the prison labor system in colonial Nigeria.
3.1 Empirical Strategy
We measure the value of prison labor to the colonial regime, referencing van Waijenburg
(2018), to estimate the value of unpaid wages to prisoners, and its relative share in expen-
diture on new construction of colonial public works.32
28Subsequently referred to as the Annual Report .
29Nigeria was amalgamated from separate regions into a single country in 1914 and although the Blue
Books data extend back to 1914, some information is missing between 1914 and 1920; thus, we start our
analysis in 1920 for completeness. The Blue Books data on prisons and public finance ends in 1938. For prison
data after 1938, we use records from the Annual Report on the Administration of the Prisons Department.
30An example of the archival data is presented in Figure A3 in the Appendix.
31No detailed data on the Native prisons administered by local chiefs was introduced in the colonial
archives prior to 1940. Available data on Native prisons in the annual reports from 1940 show that the
addition of Native prison estimates to the colonial estimates presented in this paper would almost double
the incarceration rate in 1940, from around 224 per 100,000 population to 399 per 100,000 population. This
suggests that the data we present here from 1920 to 1959 is likely an underestimation of the total level of
incarceration, and the total value of prison labor, during this period. We provide further discussion on this
in Appendix A.2.1.
32We use expenditure on new public works construction only here as a comparison as it reflects value-
adding investment in productive public works rather than just upkeep or maintenance. New expenditure
15

We calculate the overall value of unpaid wages of prison laborers in each year tas
follows:
Value of prison labort=Annual wagest×1
N
N
X
n=1
Prisonersnt (1)
This elicits an overall, gross value of benefits accruing to government consumers of
prison labor. As a measure of wages, we use the average annual market wages paid to
unskilled laborers. The wage measure comes from the colonial Blue Books which reports
annual wages paid to people classified as “Labourers and Carriers” and other “Unskilled
Labour”. This captures the wages for some of the types of work that prisoners were required
to perform, including felling trees and breaking rocks to clear areas for road and railroad
construction, as discussed in Section 2. P risoner snt is the daily average number of people
in prisons over ndays in the year from the archival records.33 This measure captures the
amount of convict labor that was available on any given day. As discussed in Section 2,
prison officials measured the value of prison labor based on the funds generated from hiring
out prisoners to other government departments for a small per diem fee.34 We compare our
estimated total value of prison labor to the colonial reported value of prison labor in the
results in Section 3.2.
The specification in Equation 1 does not factor in the costs of prisoner maintenance,
including food, clothing, housing, and prison staff salaries. The archival data report two
sets of costs for prisoner maintenance, including (i) food, which was reported as the main
represents about 40% of total, new and maintenance, public works expenditure between 1920 and 1959.
In Appendix A.3.3, we compare the value of prison labor figures to total public works spending, including
recurrent expenditure on regular maintenance of public works reported in the archives.
33Nis the total amount of prison days in the year recorded in the prison data. While the exact value
of Nis not explicitly listed in the archival data, we use the explicitly recorded ‘daily average number of
prisoners’ category in the colonial archives. A snapshot of the description of this category from the 1925
Annual Report on the Prisons Department, Southern Provinces, is shown in Figure A9 in the Appendix.
34For example, the Directors of Prisons, W.H. Beverly, E. Jackson, or W. Reeder in the southern provinces
from 1915 to 1921, recorded per diem estimates of the value of labor between 1916 and 1921 in the Lagos
colony and southern provinces for Nigeria. Using the classification of labor into skilled hard labor, unskilled
hard labor and light labor, described in Section 2, hard labor, both unskilled and skilled, was given a value
of five pence per day, with light labor given a value of three pence per day in 1916. Starting in 1917, skilled
hard labor was given a value of one shilling and six pence or 18 pence, unskilled hard labor was assigned a
value of five pence and light labor was assigned a value of three pence. The rates for unskilled hard labor
stay the same from 1918 through 1921, with no reporting on the exact value assigned to skilled hard labor
or light labor over this time. After 1921, the reports no longer included information on the per diem value
assigned to the different classes of labor.
16

cost of prisoner upkeep, and (ii) total prisoner maintenance costs, a measure that includes
all expenses involved in operating the prisons (i.e., everything from food costs, to staff
salaries, costs of transporting prisoners, equipment purchases, uniforms for staff, and any
other spending on prisons).35 Food cost represents an average of 35% of the total prisoner
cost for 1920 to 1959, ranging from 27% to 51% of the total prisoner costs over the study
period. Food cost and staff salaries accounted for over 50% of the total prisoner costs from
1920 to 1959. The total prisoner maintenance cost is the most expansive measure of the
prison upkeep cost. The net value of prison labor is the difference between the total value
of prison labor in Equation 1 and total prisoner maintenance costs. To estimate the relative
value of prison labor, we divide the results from Equation 1 by public works expenditures,
prison expenditures and overall expenditure figures from the Blue Books. We present the
results on the net and relative values of prison labor in Section 3.3.
Figure 3a shows the trends in the reported average annual wage and prisoner food and
overall maintenance costs. The total reported prisoner upkeep cost closely tracks the wage,
reflecting increases in staff salaries over time, with a steep increase after 1940. Prisoner food
cost follows a similar pattern, although the post-1940 increase in cost is less steep than the
wage and total prisoner cost. Figure 3b shows the daily average number of prisoners over
the study period. Wages remained above prisoner food costs in all years, and above total
prisoner costs in over 51% of the years between 1920 and 1959. The daily average number in
prison fluctuated between 1920 and 1940, increasing through 1930, then decreasing between
1930 and 1940, before sharply increasing after 1943. Interestingly, the daily average number
of prisoners also appears to track the average annual wage in Figure 3a. There is a positive
correlation (0.87, p < .001) between the daily average numbers in prison and the average
annual wage to unskilled laborers.
We estimate various versions of Equation 1 in alternate specifications, including esti-
mates using alternate wage measures, adjusting for inflation, and addressing any potential
bias in prisoner estimates by computing a weighted average measure of people committed
to prison for penal imprisonment in each year. The trends in the results remain unchanged
and are detailed in Appendix A.3.
35An example of one breakdown of these costs over 1919 to 1921 from the colonial archives for prisons in
the southern provinces is shown in Figure A11 in Appendix A.3.
17

3.2 Value of Prison Labor Results
Figure 6 presents our estimates of the total gross value of prison labor based on Equation 1,
along with a comparison to the colonial prison officials’ own reports of the value of prison
labor based on fees remitted to the Prison department for prisoners’ labor.36 While our
estimates of the value of prison labor are consistently higher than the colonial governments’
own reports, both measures follow similar trends, and the values are close to each other prior
to 1945. There is a positive correlation (0.7, p < 0.001) between our estimates and the colonial
reported values of prison labor. The estimated total gross value of prison labor starts out
around 178,498 pounds in 1920 and fluctuates- first decreasing, and then increasing through
1927, before mostly declining through 1943, then increasing sharply afterward, peaking at
1,532,634 pounds in 1959.37 The average estimated gross value of prison labor is 313,742
pounds over the colonial period. Although prisoners were not paid, the exact amount of
the payment remitted to the Prisons department from other government agencies for their
labor was recorded for the southern provinces in a few years between 1919 and 1925. These
payments were the per diem prices set by the Prisons department for a prisoner’s labor based
on the level of skilled labor required, as discussed in Section 2.3. We compile these estimates,
and compare these prisoner prices with the daily market wage rate for similarly skilled
workers in the southern provinces.38 Prisoners performing unskilled hard labor, who made
up the majority of the prison population, as discussed in Section 2, were assigned a value
between 60%-80% below the market wage rate. Colonial prison officials were consistently
undervaluing prisoners’ labor to keep administration costs for peer government departments
low, while attempting to balance budgets.39
3.3 Prisoner Costs and Relative Value of Prison Labor
We calculate the difference between the total value of prison labor and the total prisoner
maintenance costs, or the net value of prison labor, and compare these estimates to the
colonial government’s spending on public works, prisons and overall colonial expenditure.40
36We provide more detail and numbers in Table A2 of Appendix A.3.
37Given the debates around the choice of the price index for colonial Africa, we present the figures in
nominal terms here (Frankema and Van Waijenburg, 2012). We present the real estimates in Appendix A.3,
and the trends remain unchanged.
38The estimates are shown in Figure A10 of Appendix A.3.
39This is confirmed in the report written by Prison Inspector Beverley in the 1915 Annual Report on
Prisons, in which he states that values assigned to prisoners’ labor are below “wages demanded by workmen
in civil life”. He recommends a doubling of values to balance prison expenditure amounts, illustrating the
balance sheet calculus that appeared to drive the setting of prison labor values.
40There is still a positive correlation (0.5, p < 0.01) between our net value estimates and the colonial
reported value of prison labor described in Section 3.2 as shown in Figure A12 in the Appendix.
18

Table 1 reports the estimates as decadal averages from 1920 to 1959.41 Even after sub-
tracting out the extensive measures of prisoner maintenance costs described in Section 3.1,
the net value of prison labor is nonnegative and strictly positive in 60% and 57% of years,
respectively, in colonial Nigeria.
Over the four decades of colonial data available, the net value of prison labor, less
prisoner food costs, remains strictly positive, with an average of 195,260 pounds. When we
estimate the net value of prison labor using all prisoner maintenance costs reported, the
mean falls to 31,674 pounds. The only decade in which the net value of prison labor, less
total prison costs, becomes negative (at -16,891 pounds) is during the World War II period
between 1941 and 1950, when, as discussed in Section 2.2, there was a relative increase in the
use of military conscript labor. The net value figure increases notably (to 160,805 pounds) in
the post-war period from 1951 to 1959, following a flurry of public works construction activity
right before Nigeria’s independence in 1960. On average, the gross value of prison labor or
unpaid wages to prison laborers was more than double the amount spent by the colonial
government on public works between 1920 and 1959. After adjusting for extensive measures
of prisoner maintenance costs, the share of the net value of prison labor