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Is Proportional Representation More Favourable to the
Left? Electoral Rules and Their Impact on Elections,
Parliaments and the Formation of Cabinets
Holger Döring and Philip Manow
British Journal of Political Science / FirstView Article / August 2015, pp 1 - 16
DOI: 10.1017/S0007123415000290, Published online: 24 August 2015
Link to this article: http://journals.cambridge.org/abstract_S0007123415000290
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Holger Döring and Philip Manow Is Proportional Representation More Favourable to the Left?
Electoral Rules and Their Impact on Elections, Parliaments and the Formation of Cabinets. British
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B.J.Pol.S., Page 1 of 16 Copyright © Cambridge University Press, 2015
Is Proportional Representation More Favourable
to the Left? Electoral Rules and Their Impact on
Elections, Parliaments and the Formation of Cabinets
HOLGER DÖRING AND PHILIP MANOW*
How do electoral rules affect the composition of governments? It is a robust ﬁnding that countries with
majoritarian rules more often elect conservative governments than those with proportional representation
(PR) electoral systems. There are three explanations for this pattern. The ﬁrst stresses the impact of
voting behaviour: the middle class more often votes for right-wing parties in majoritarian electoral
systems, anticipating governments’redistributive consequences. The second explanation is based on
electoral geography: the regional distribution of votes may bias the vote-seat translation against the Left
in majoritarian systems due to the wide margins by which the Left wins core urban districts. The third
explanation refers to party fragmentation: if the Right is more fragmented than the Left in countries with
PR, then there is less chance of a right-wing party gaining formateur status. This study tests these three
hypotheses for established democracies over the entire post-war period. It ﬁnds the ﬁrst two mechanisms
at work in the democratic chain of delegation from voting via the vote-seat translation to the formation
of cabinets, while party fragmentation does not seem to co-vary as much as expected with electoral rules.
These ﬁndings conﬁrm that majoritarian systems have a substantive conservative bias, whereas countries
with PR show more differentiated patterns.
We know that electoral rules systematically co-vary with government composition. Right-wing
governments are more likely to form under majoritarian rules, whereas left-wing governments
are more frequent with proportional representation (PR).
There are three potential explanations
for this ﬁnding. The ﬁrst stresses the impact of voting behaviour: citizens vote more often for a
right (left) party in majoritarian electoral systems (with PR), anticipating the redistributive
consequences of right or left governments in either system.
The second explanation points to
the impact of electoral geography: the regional distribution of votes may bias the vote-seat
translation in favour of the Right in majoritarian systems due to the wide margins by which the
Left wins core urban districts.
The third explanation is based on party-system fragmentation:
a higher degree of fragmentation on the Right in countries with PR means less chance of a
right-wing government forming.
* Centre for Social Policy Research, University of Bremen (email: firstname.lastname@example.org); Centre for
Social Policy Research, University of Bremen and Institute for Advanced Study, Berlin (email: manow@
uni-bremen.de). Previous versions of this paper were presented at the 2011 APSA Annual Meeting in Seattle,
a CRC 597 workshop in Bremen, the 2012 EPSA General Conference in Berlin, the Europeanists Conference
in Amsterdam 2013, the 2013 ECPR General Conference in Bordeaux and a 2013 workshop on democratic
governments in Lund. We would like to thank Michael Becher, Dominik Duell, Sona Golder, Vera Tröger
and Melike Wulfgramm for their helpful comments on the paper and Inken Behrmann for her research
assistance. Both authors contributed equally to this work. Data replication sets are available at https://
dataverse.harvard.edu/dataverse/BJPolS and online appendices are available at http://dx.doi.org/doi:10.1017/
Cf. Iversen and Soskice 2006, 166, Table 1.
Iversen and Soskice 2006.
Gudgin and Taylor 1979; Rodden 2010.
Martin and Stevenson 2001; Rokkan 1970.
All three accounts highlight the importance of electoral rules, but emphasize different stages
in the democratic chain of delegation at which the impact of PR or majoritarian rules should be
felt, namely at the voting stage (voter-behaviour hypothesis), during the translation of votes into
seats (political-geography hypothesis) or in the process of government formation/coalition
building (party-fragmentation hypothesis). In this article we use a new dataset on parliamentary
and governmental composition for all major Western democracies since 1945
to examine the
explanatory merits of each of these arguments. We measure and compare countries’average
position on the left-right scale at the electoral, parliamentary, and cabinet level in the PR and
majoritarian systems –that is, we compare their weighted election, parliament and cabinet
means. We do not do this with any intention of entering into the recent debate on whether PR or
majoritarian rules lead to a higher ‘ideological congruence’between the citizenry and political
rather, we are in search of the systematic effects of electoral rules on the ideological
composition of governments.
Thereby we contribute to the recent debate on the partisan effects of electoral rules,
understanding of ‘elections as an instrument of democracy’
and make a contribution to the literature
on comparative political economy, which has long highlighted the important redistributive effects of
We also add to the coalition formation literature by underscoring the partisan effects
of electoral rules on the composition of cabinets via the fragmentation of party systems.
The article is organized as follows. We brieﬂy summarize the three mechanisms that serve to
predict the systematic left/right differences between the two electoral systems in translating votes
into parliamentary seats into cabinet posts. Then we derive empirical implications from each of these
explanations. Next we describe our data and analyse the political positions at all three stages of the
democratic chain of delegation, inquiring into the source of the conservative bias of majoritarian
electoral systems or the progressive bias of PR. The article then ends with a brief conclusion.
VOTING BEHAVIOUR,THE VOTE-SEAT TRANSLATION AND THE FORMATION OF
It is an established ﬁnding that parties of the Right are more likely to hold governmental power
under majoritarian rules. But how exactly do electoral rules impact the ideological composition
of government? One explanation recently put forward points to differences in electoral
behaviour under the two electoral rules.
Iversen and Soskice base their argument on a formal
model with three classes –lower, middle and upper –and a non-regressive tax system (which
will not redistribute income ‘upward’from the lower to the middle or upper class, or from the
middle to the upper class). A majoritarian electoral system will give rise to a two-party system
with a centre-left and centre-right party.
The upper class will vote Right, against income
redistribution, and the lower class will vote left, in favour of redistribution.
Therefore the voting behaviour of the middle class becomes decisive. Confronted with the
choice between a centre-left and a centre-right government, the middle class more often votes right
than left, fearing that a government led by a left-wing party will deviate from its median-voter
Döring and Manow 2013.
Golder and Stramski 2010; Huber and Powell 1994; Powell 2009.
Iversen and Soskice 2006; Rodden 2010.
Gourevitch and Shinn 2007; Persson and Tabellini 2000; Rogowski 1987.
Martin and Stevenson 2001; Tavits 2008.
Iversen and Soskice 2006.
Duverger’s Law; Neto and Cox 1997.
2DÖRING AND MANOW
platform after the election and cater exclusively to the interests of the lower class. The
middle-class voter’s fear is that a left-wing party will tax the upper and middle classes to the
more or less exclusive beneﬁt of the lower class. A right-wing party’s deviation from its
platform while in power is perceived as less damaging to middle-class voters since this party
would still not tax the rich or the middle class. In other words, the worst the middle class could
expect under a right-wing government is that it would neither have to ﬁnance income
redistribution nor beneﬁt from it. This is in contrast to a left-wing government that might force
the middle class to ﬁnance income redistribution without itself beneﬁting from it. Hedging
against the ever-present (albeit small) possibility of a party’s post-electoral opportunism,
middle-class voters prefer to vote centre-right.
Under PR (that is, in a multiparty system),
the middle class’s choice is different. Here a genuine middle-class party can form a coalition
with a party of the Left and both can credibly commit (via the threat to exit from a coalition)
to a programme of taxing the rich and sharing the revenue; in coalitions with middle-class
parties, the Left will be in government more often and income redistribution will thus be more
Iversen and Soskice’s main argument is about voting behaviour: voters anticipate the
redistributive consequences of parties’eventual post-electoral opportunism. Were we to follow
their argument, we should expect to see the major effects of electoral rules as early as the
electoral stage itself. Empirically we should then expect to observe in a comparison of
countries’election means –that is, their vote-share weighted average left-right positions –an
election mean in majoritarian systems that is systematically and signiﬁcantly to the right of the
election mean under PR. This is our Hypothesis 1, the electoral-behaviour hypothesis.
An alternative argument points to differences in the vote-seat translation between majoritarian
and PR systems. Jonathan Rodden has reminded us why majoritarian electoral systems –
irrespective of voting behaviour –might favour the formation of conservative governments:
electoral geography. For various reasons, low-income earners are more likely to live in densely
populated areas –this of course has been true since the high tide of industrialization and
urbanization, and holds true today in most post-industrial societies owing to the availability of
cheap housing and transportation.
Since income is a strong predictor of vote choice, this
becomes an electoral disadvantage for the Left in majoritarian systems. Under majoritarian rules
the Left will win some districts by very wide margins but will lose many districts by small
margins; in other words, under majoritarian electoral rules a left-wing party will suffer from a
high number of ‘wasted votes’. This ‘built-in’bias against the Left in majoritarian systems has
been observed for quite some time.
It is said to be ‘an almost inevitable feature resulting from
the concentration of Labour votes in industrial areas’
–and, we might add, also in today’s
The subsequent empirical expectation is that the parliament’s position on the left/right scale
should be to the right of the election outcome in countries with majoritarian electoral systems. By
contrast, given that proportionality in the vote-seat translation is the deﬁning feature of PR
systems, we must not expect any signiﬁcant and systematic differences between the electoral and
parliamentary positions under these electoral rules. Hence, according to the political-geography
argument, differences between the two electoral systems should materialize at the parliamentary
level in majoritarian systems when voting shares have been translated into seat shares.
See Iversen and Soskice 2006.
Gudgin and Taylor (1979, 78) with further literature.
Rydon (1957) as quoted in Gudgin and Taylor (1979, 78).
Impact of Electoral Rules on Elections, Parliaments and Cabinet Formation 3
More speciﬁcally, we would expect that the parliament mean under majoritarian rules is to the
right of the election mean, whereas in countries with PR neither should differ very much. This
then is our Hypothesis 2, the political-geography hypothesis.
The third explanation for the nexus between electoral rules and government composition
stresses the importance of party fragmentation. Greater fragmentation of the Right under PR
may render the formation of a centre-right coalition cabinet more costly and therefore less
This is an argument going back to Lipset and Rokkan’s cleavage theory and to early
theories of coalition formation.
As Rokkan in particular has argued,
historically inﬂuenced the choice of electoral system; where societal cleavage structures have
led to a more fragmented Right, the switch to PR was more likely. According to Rokkan and
more recently Boix,
PR was used as a safeguard by fragmented parties on the Right to
suppress potential landslide victories of the rising and more uniﬁed Left under majority-runoff
or ﬁrst-past-the-post electoral rules. One implication of this argument is that PR should
positively co-vary with party fragmentation to the right of the political spectrum. In this case,
though, it would also be less likely for a right-wing party to become the strongest party, receive
formateur status and subsequently lead a coalition cabinet.
Studies of coalition building have generated robust predictions about the number of parties
a cabinet includes.
Theoretical models predict that cabinets tend to be ideologically compact
and that they try to limit the absolute number of coalition partners –that is, they are minimum-
This is explained by efforts to gain ideological coherence, by attempts to avoid the
exponentially increasing transaction costs of managing a greater number of coalition partners,
and by parties’interest in dividing ‘the spoils of power’among as few coalition partners as
It is an established ﬁnding that coalitions with a smaller number of parties are more
likely to form, and that the largest party in parliament tends to be in the cabinet.
fragmentation of the Right under PR would then mean that, more often than not, the cabinet
position tends to shift to the Left when parliamentary seats are translated into cabinet posts. By
contrast, at the stage of government formation, no independent tendency for a shift to either side
must necessarily be expected under majoritarian rules –apart from the fact that a previous
conservative bias at the electoral and/or parliamentary stage would render the formation of a
conservative government more likely. This then is our Hypothesis 3, the party-fragmentation
hypothesis, which lets us expect, ﬁrst, a higher party fragmentation on the Right in PR countries
compared to countries with majoritarian electoral rules and, secondly, a shift of the cabinet
mean to the Left of the parliament mean under PR due to this higher fragmentation of the Right.
Let us brieﬂy summarize where exactly in the democratic chain of delegation the three
different explanations would expect the impact of electoral rules to materialize (see Table 1).
Hypothesis 1 (electoral behaviour) predicts that the electoral position in countries with
majoritarian rules will be to the right of the electoral position in countries with PR (Hypothesis 1).
Hypothesis 2 (political geography) leads us to expect a shift to the right in the translation of
votes into seats under majoritarian rules –that is, a parliamentary position to the right of the
electoral position in these electoral systems –whereas no such shift is expected under PR
Martin and Stevenson 2001.
Lipset and Rokkan 1967; Riker 1962.
Tavits 2008; Warwick 1996.
de Swaan 1973.
Mershon 2002; Riker 1962.
Martin and Stevenson 2001, 42.
4DÖRING AND MANOW
TABLE 1Electoral Rules and Their Impact on Government Composition: Three Causal Mechanisms
chain Elections (Vote-seat
translation) Parliaments (Cabinet formation) Governments
Explanation Voting behaviour
Mechanism Voters vote more
Majoritarian systems put (left) parties with
a regionally concentrated electorate at
Higher party fragmentation of the Right under
PR makes formateur status of a conservative
party less likely
Hypotheses Hypothesis 1: the electoral
majoritarian rules is to the
right of the electoral
position in PR countries
Hypothesis 2: majoritarian electoral rules
shift the parliamentary position to the
right of the electoral position
Hypothesis 3a (descriptive): the effective
number of parties (ENP) on the Right is
higher than the ENP on the Left in PR
Hypothesis 3b (analytical): the higher ENP on
the Right shifts the cabinet position to the
Left of the parliamentary position in PR
Measurement Election mean Distance election/
parliament mean Parliament mean Distance parliament/
cabinet mean Cabinet mean
Iversen and Soskice (2006).
Martin and Stevenson (2001); Rokkan (1970).
Impact of Electoral Rules on Elections, Parliaments and Cabinet Formation 5
(Hypothesis 2). Finally, Hypothesis 3 (party fragmentation) ﬁrst predicts a higher degree of
party fragmentation of the Right in PR countries (Hypothesis 3a) and subsequently predicts the
impact of party fragmentation on government formation under these electoral rules, independent
of any possible bias at previous stages of the democratic chain of delegation (Hypothesis 3b).
More speciﬁcally, we would expect to observe that the cabinet position shifts to the Left of the
parliamentary position in PR countries, but we would not expect to ﬁnd a fragmentation effect
to either side, the Left or the Right, in countries with majoritarian electoral rules.
Before testing the relative explanatory power of the three hypotheses, we need to address one
methodological problem that derives from the fact that of course our three stages in the
democratic chain of delegation are mutually interdependent. For instance, if majoritarian
electoral rules reveal a conservative bias at the electoral and/or parliamentary level, a right-wing
government is more likely to form as a simple consequence of the prior bias(es). Slightly more
complicated is an effect in the reverse direction: if voters anticipate that further down in the
delegation chain the mechanics of the vote/seat translation or the logic of government formation
lead to a right (left) bias in majoritarian (PR) systems, they might adjust their voting behaviour
accordingly in order to counterbalance this bias.
Outcome-interested voters would then be less
likely to vote for the Right (Left) under majoritarian rules (under PR).
It is relatively easy to deal with the ﬁrst interaction effect in our analysis by controlling for the
ideological position of the preceding stage in the democratic chain of delegation when analysing
the effects of electoral rules on the following stage –that is, we control for the election mean
when analysing the impact of electoral rules on the composition of parliament, and control for
the parliament mean when analysing the impact of electoral rules on the cabinet’s position. In
this way we can identify additional effects at later stages in the democratic chain of delegation
whenever they are present. An alternative methodological approach we employ is to estimate
parliamentary and cabinet positions together in a simultaneous-equation framework. Given our
study’s design, the problem of anticipatory voting cannot be solved empirically; fortunately it is
also less relevant for our analysis because it causes us to err against our own hypotheses. The
average voter who anticipates, say, the right-wing bias of majoritarian rules further along the
chain of delegation and seeks to counterbalance it will be less likely to vote for the Right.
Similarly, should the average voter who aims at a particular government anticipate that a
left-wing party is more likely to enjoy formateur status under PR, (s)he will on average be less
likely to vote for the Left. Should we then –in accordance with Hypothesis 1 –still observe an
election mean in majoritarian systems that is to the right of the election mean under PR, which
we do observe (see below), we do so despite the fact that some outcome-oriented voters might
have adjusted their vote to counterbalance the inherent bias of electoral rules. In other words,
absent anticipatory voting, our results could only have been more emphatic. We can therefore
afford to ignore voters’potential anticipations in the following analysis, to which we now turn.
ELECTIONS,PARLIAMENTS AND THE COMPOSITION OF GOVERNMENT
For our investigation into the impact of electoral rules on the composition of governments, we
include parliamentary democracies (and exclude presidential systems) in the Organisation for
Economic Co-operation and Development (OECD) with at least thirty years of stable democratic
rule. Our units of observation are the left/right position of the electorate as well as the parliament
and cabinet at each instance of cabinet formation. For twenty-two countries we cover all elections
Cf. Kedar 2005a, 2005b.
6DÖRING AND MANOW
and cabinets over the entire post-war period (from 1945–49 to 2013), and starting from the 1970s
for Greece, Spain and Portugal. For France and New Zealand we include separate electoral
classiﬁcations for their time under PR and majoritarian rules. None of the other countries
completely transitioned from a majoritarian to a PR system or vice versa, although many countries
enacted minor electoral reforms.
The data cover 421 elections and 675 cabinets. Our ﬁndings
therefore have a much larger empirical basis than the study by Iversen and Soskice.
The dataset combines information regarding election results and parliamentary and
governmental composition with data about parties’political positions.
measure is a composite index based on four established party-expert surveys.
locating elections, parliaments and governments on the left-right continuum, we provide
measures for the weighted mean (that is, the political centre of gravity)
at all three levels. To
calculate these measures we weight parties’left/right positions by vote share at the electoral
level and by seat share for all parties in parliament and all cabinet parties, respectively. We
rescale the original 0 to 10 interval of our data source to a −5 to 5 interval. Caretaker cabinets
are excluded from the analysis.
We also replicate our analyses with data from the Comparative Manifesto Project (CMP).
The CMP data provide time-varying information, in contrast to the static expert-survey based
measures used in ParlGov. Relevant for our purpose is the CMP’s right/left-score (‘rile’). Yet its
validity and reliability is contested, and there is doubt as to whether the CMP measure provides
valid information across countries and over time (see the Appendix for a more detailed
We therefore interpret the replication results with some degree of caution.
With respect to the classiﬁcation of electoral systems, we rely on Lijphart
Bormann and Golder.
For two potentially controversial cases we follow Bormann and Golder
and classify the Japanese electoral systems as majoritarian and the Irish single transferable vote
(STV) system as PR (for a more detailed discussion of these two cases, see the Appendix) –but
our results hold independent of those classiﬁcations. Finally, France underwent electoral reform
in 1958, as did New Zealand in 1994. New Zealand used a ﬁrst-past-the-post system until 1994
and has employed a mixed-member proportional system since 1996. France used PR electoral
rules under the Fourth Republic (before 1958) and a majority-runoff system during the Fifth
Republic, except for the 1986 election to the Assemblée Nationale, when PR was employed. We
therefore classify the respective periods as majoritarian and PR for the two countries.
We begin the presentation of our empirical ﬁndings with some descriptive statistics about
government composition. The mean party-political position of all cabinets in our dataset is 0.6
on the −5 to 5 left/right interval. Once we split our countries into the two groups, we see that all
six majoritarian countries are located to the right of this mean (see Figure 1).
Iversen and Soskice 2006.
Döring and Manow 2013.
Benoit and Laver 2006; Castles and Mair 1984; Hooghe et al. 2010; Huber and Inglehart 1995; Steenbergen
and Marks 2007; for more information, see the Appendix.
Gross and Sigelman 1984.
Budge et al. 2001; Klingemann et al. 2006; Volkens et al. 2013.
Cf. Gemenis (2013) for a balanced review.
Bormann and Golder 2013.
Impact of Electoral Rules on Elections, Parliaments and Cabinet Formation 7
Figure 1 shows that all countries with majoritarian systems display a signiﬁcant shift to the
right at the cabinet level. Within that general rightward trend, Japan appears to be a particularly
strong case. In combination with the controversial classiﬁcation of the Japanese electoral system
we decided to make prudent estimates and therefore exclude Japan from the following analysis.
For PR countries we ﬁnd that cabinets in Norway and Sweden are located clearly to the left of
the centre, whereas all other PR countries are at the centre or somewhat to the right. However,
comparing our two groups of countries we observe that almost all PR cabinets are to the left of
cabinets in countries with majoritarian electoral rules. As a ﬁrst observation we can
therefore conﬁrm the literature’s general ﬁnding that majoritarian electoral rules reveal a
What do we observe once we compare election, parliament, and government means for
majoritarian and proportional systems (see Figure 2)? We ﬁnd that majoritarian systems have a
substantial right-wing bias at all three levels: (1) voters tend to vote more to the right than those
in PR countries. Subsequently, on both the parliamentary and cabinet levels, the political mean
moves even further to the right and we thus observe in countries with majoritarian rules, on top
of the more conservative voting behaviour (2) a ‘mechanical effect’when vote shares are
translated into seat shares, plus (3) a further shift to the right when it comes to the formation of
governments. Figure 2 does not tell us, though, whether this last effect is an additional or
aggregate effect due to the preceding bias(es). In proportional systems, by contrast, the mean
positions at all three levels do not differ greatly.
New Zealand (PR)
Fig. 1. Cabinet positions in majoritarian and PR countries
Note: mean left/right cabinet position with 95 per cent conﬁdence interval. Cabinet positions are seats
weighted left/right positions for all parties in cabinet and are calculated for each instance of cabinet
formation. Left/right party position interval from −5 to 5 (left to right). Source: Döring and Manow (2013).
8DÖRING AND MANOW
A simple regression model estimating the electoral position with a PR variable as well as
estimating the parliamentary position with the electoral position and a PR variable shows the
expected effects of electoral rules (see Table 2, Models 1a and 2a). The election mean in PR
systems is to the left of majoritarian systems and the parliamentary mean shows an additional
shift to the left.
These results therefore support both the voting-behaviour (Hypothesis 1) and the political-
geography hypothesis (Hypothesis 2). Whether or not we also observe an additional fragmentation
effect (Hypothesis 3b) can only be answered when analysing the impact of fragmentation on
government composition while controlling for parliamentary composition (see below).
Yet we want to emphasize that –contrary to what Hypothesis H3b would lead us to expect –
Figure 2 does not show a leftward shift of the cabinet mean in PR countries. When we compare
the electoral outcome with the parliament mean, there is almost no difference between the two
positions in PR systems, whereas there is a statistically signiﬁcant ‘mechanical effect’in
majoritarian systems, shifting the mean to the right when translating votes into seats. In
addition, the mean is further moved to the right under both electoral rules at the level of cabinet
formation –and not to the left under PR only, as Hypothesis 3b predicted. The effect is even
stronger under majoritarian rules than in PR systems.
Replicating our analysis with CMP data basically conﬁrms these patterns (see Models 1b and 2b,
Table 2; see also Figure A1). In majoritarian systems the parliamentary mean is to the right of
election parliament cabinet
Fig. 2. Electoral, parliament and cabinet positions in majoritarian and PR countries
Note: mean left/right position of electorate (vote share of parties), parliaments (seat share of parties) and
cabinets (seat share of cabinet parties) with 95 per cent conﬁdence interval. Electoral and parliamentary
positions are calculated for each election (396 observations) and cabinet positions for each instance of cabinet
formation (622 observations). Japan is excluded from majoritarian countries. Left/right party position interval
from −5 to 5 (left to right). Source: Döring and Manow (2013).
Impact of Electoral Rules on Elections, Parliaments and Cabinet Formation 9
the election mean, and we observe a further rightward shift at the stage of cabinet formation. By
contrast, almost no differences can be noted for the three levels under PR; however, the high
variance of the CMP-based left/right positions leads to greater uncertainty and therefore the
differences between the two electoral systems appear less clear-cut.
Table 3 provides additional information on differences in cabinet composition between
majoritarian and proportional electoral systems, on the distribution of Left, Centre and Right
governments under the two electoral systems and on the extent of party fragmentation in both
Similar to Iversen and Soskice,
we distinguish Left, Centre and Right cabinets; but whereas
Iversen and Soskice exclude centrist governments from their analysis, we classify cabinets with
more than one-third of their parliamentary seats to the left and right of the parliamentary mean
as Centre cabinets. The majority of these cases are grand coalitions including the major party
from the Left and the Right, as for example in Austria where a grand coalition of Social
Democrats and the People’s Party ruled for most of the post-war period. All other cabinets with
two-thirds of the (coalition) parties’seats on one side of the parliamentary mean fall either into
our left or right category. Table 3 supports previous ﬁndings that majoritarian electoral systems
lead to either Right or Left (but not Centre) cabinets with a higher number of cabinets to the
right of the political spectrum: two-thirds of all cabinets are to the right under majoritarian rules.
In contrast to Iversen and Soskice,
however, our data show that PR countries have an almost
equal share of Left, Centre and Right cabinets.
With respect to party-system fragmentation, Table 3 provides evidence of different
patterns among the two types of electoral systems as expected by Hypothesis 3a. Columns 5
and 6 report the effective number of parties (ENP) to the right and the left of the
parliamentary mean. In accordance with Hypothesis 3a, we do observe a higher ENP on
the right in PR systems (ENP: 2.2 vs. 1.8), and a simple regression of right-ENP on an
electoral system dummy (controlling for country effects) conﬁrms the result (not reported).
TABLE 2Impact of Electoral Rules on Election and Parliament Mean, ParlGov and
Model 1a Model 1b Model 2a Model 2b
Election mean 0.95*** 1.01***
PR −0.39*** −0.18 −0.20*** −1.58***
(0.09) (3.63) (0.05) (0.30)
Constant 0.51*** −2.98 0.24*** 1.69***
(0.06) (3.28) (0.05) (0.26)
N396 382 396 382
0.191 0.000 0.779 0.974
Note: country-clustered robust standard errors in parentheses. Japan excluded (twenty-ﬁve
elections); ParlGov-based left/right scale (−5 to 5); CMP left/right (‘rile’) scale (−100 to 100).
*p <0.10, **p <0.05, ***p <0.01
Iversen and Soskice 2006, 166.
Iversen and Soskice 2006, Table 1.
10 DÖRING AND MANOW
By contrast, in all six of the majoritarian countries except Australia, the Left is either more
fragmented or shows a degree of fragmentation that is at least equal to that of the Right. Australia
is the only country with majoritarian rules in which fragmentation of the Right exceeds that of the
Left –that is, the Liberal Party and the National (Country) Party vis-à-vis Labour.
The preceding analysis conﬁrmed our hypotheses regarding voting behaviour (Hypothesis 1)
and electoral geography (Hypothesis 2) and lent initial support to the fragmentation hypothesis
(Hypothesis 3a); but it also raised certain doubts as to whether party fragmentation indeed
translates into a progressive bias at the stage of cabinet formation in PR countries (Hypothesis 3b;
cf. Figure 2).
We now wish to test whether the process of cabinet formation comes with an additional
progressive bias under PR (Hypothesis 3b). Let us brieﬂy discuss the logic of such an analysis
for a case of perfect congruence between election, parliament and cabinet positions (a) and let
us also add a word about the structure of our data and the design of our analysis (b).
(a) In a highly proportional electoral system, the composition of parliament would truly
represent the outcome of an election. In other words, the parliament mean would not –at least
TABLE 3Parameters for All Countries (1945–2013)
ENP Cabinet share
Electoral system Country First Disprop. Left Right Left Centre Right
(1) (2) (3) (4) (5) (6) (7) (8) (9)
Majoritarian AUS 1946 9.6 1.0 1.6 0.38 0.00 0.62
CAN 1945 12.6 1.6 1.2 0.66 0.00 0.34
FRA-II 1958 16.7 1.7 1.8 0.29 0.08 0.63
GBR 1945 10.9 1.2 1.1 0.44 0.00 0.56
JPN 1946 9.2 2.1 1.3 0.05 0.03 0.92
NZL-I 1946 11.2 1.0 1.0 0.31 0.00 0.69
1.4 1.3 0.36 0.02 0.63
Proportional AUT 1945 2.4 1.2 1.5 0.25 0.59 0.16
BEL 1946 3.3 2.1 3.7 0.08 0.59 0.33
CHE 1947 2.7 2.2 3.0 0.02 0.50 0.48
DEU 1949 2.6 1.3 1.5 0.31 0.11 0.58
DNK 1945 1.5 2.0 2.8 0.56 0.00 0.44
ESP 1977 7.1 1.3 1.5 0.58 0.00 0.42
FIN 1945 3.0 2.1 3.1 0.07 0.66 0.27
FRA-I 1946 5.0 2.9 2.6 0.19 0.35 0.46
GRC 1974 9.2 1.4 1.1 0.59 0.00 0.41
IRL 1948 4.3 1.6 1.9 0.04 0.09 0.88
ISL 1946 3.4 2.9 1.2 0.21 0.49 0.30
ITA 1946 3.2 2.1 2.2 0.08 0.05 0.87
LUX 1945 4.6 1.6 1.9 0.00 0.53 0.47
NLD 1946 1.3 1.9 2.8 0.00 0.56 0.44
NOR 1945 4.6 1.7 2.6 0.74 0.04 0.23
NZL-II 1996 2.9 1.5 1.9 0.52 0.00 0.48
PRT 1976 5.4 1.7 1.4 0.40 0.08 0.52
SWE 1948 2.0 1.3 2.9 0.75 0.00 0.25
1.8 2.2 0.30 0.26 0.44
Note: weighted mean (duration) of all observations presented. Disprop. –disproportionality (least
squares index ) of the vote-seat translation; ENP –effective number of parties (seats) to the left (right)
of the parliamentary position (weighted mean). Source: Döring and Manow (2013).
Impact of Electoral Rules on Elections, Parliaments and Cabinet Formation 11
not in any systematic or signiﬁcant way –deviate from the election mean. Electoral rules would
be neutral, favouring neither the Left nor the Right. But cabinets, a subset of parties in
parliament, would still typically be located either to the left or right of the parliamentary
position. Yet due to regular alternation in ofﬁce we would again expect no aggregate (mean)
difference in the political positions of parliaments and cabinets over time. Therefore, under
perfect proportionality along with regular alternation in ofﬁce, we would not expect any impact
exerted by the variables we present.
(b) A discussion of the particular structure of our data is also warranted. The data in our
analysis are grouped at the country level, and we measure the positions of parliaments and
cabinets and the ENP at the country level as well. The variables show a higher between-country
than within-country variance; however, cabinet positions may vary substantially within
countries due to alternation in ofﬁce. Given this structure we use a linear-regression model with
country-clustered robust standard errors. We study the impact of our explanatory variables,
particularly party fragmentation, on the positions of cabinets while controlling for the
parliamentary position (see Table 4). To be more speciﬁc: our linear multivariate model predicts
the distance of the cabinet mean from the parliament mean (weighted means) in order to detect
any additional inﬂuence of electoral rules on government composition in our two groups of
electoral systems. And now we restrict our analysis to an inquiry into whether this ﬁnding is
exclusively due to the conservative bias of majoritarian rules at the electoral and parliamentary
levels or whether there is an additional bias at the cabinet-formation stage due to systematic
differences in party fragmentation between the Right and the Left.
Models 1 and 2 in Table 4 include all countries (except Japan, see above) in our sample, and
the ﬁrst model tests the complete speciﬁcation. We split our sample for each of the two types of
electoral systems that we discuss (Models 3 and 4), further clarifying the disparate impact of our
explanatory variables. To check for robustness we remove two potentially controversial cases in
TABLE 4Determinants of Parliament-Cabinet Distances
All All Majoritarian PR Sub-sample Fixed effects
(Model 1) (Model 2) (Model 3) (Model 4) (Model 5) (Model 6)
Left-ENP 0.54*** 0.55*** 0.36 0.53** 0.59*** 0.42**
(0.19) (0.17) (0.29) (0.19) (0.21) (0.16)
Right-ENP −0.30*** −0.31*** −0.36 −0.31*** −0.31*** −0.37***
(0.09) (0.09) (0.22) (0.10) (0.09) (0.12)
Elect.-Parl. 0.95*** 1.32 0.40 0.94*** 1.37***
Distance (0.32) (0.62) (0.59) (0.32) (0.42)
PR 0.02 −0.21 0.01
(0.15) (0.16) (0.16)
Constant −0.19 0.06 0.05 −0.11 −0.23 0.16
(0.18) (0.19) (0.58) (0.29) (0.20) (0.27)
N621 621 145 476 578 621
0.148 0.109 0.220 0.127 0.155 0.132
Note: country-clustered robust standard errors in parentheses. Dependent variable: distance of
weighted mean left/right position between parliament and cabinet (Japan excluded). Independent
variables: PR –proportional electoral system; Left (Right); ENP –effective number of parties to the
left (right) of the parliamentary position (weighted mean); Elect.-Parl. distance –distance between
(weighted mean) Left/Right position of electorate (vote share) and parliament (seat share). Model 5:
sub-sample without Ireland (STV) and Switzerland (cabinet status) (see Appendix). Source: Döring
and Manow (2013). *p <0.10, **p <0.05, ***p <0.01
12 DÖRING AND MANOW
Model 5: Ireland, since the classiﬁcation of its electoral system is open to debate (see above),
and Switzerland due to its particular type of cabinet formation (see the Appendix for a more
detailed discussion). We add a re-estimation of Model 1 with country-ﬁxed effects in Model 6,
and estimate our main models using CMP data (Table A5).
We start by discussing the effect of party-system fragmentation on the position of cabinets.
Hypothesis 3b leads us to expect that a higher fragmentation of the Right under PR makes the
formation of a conservative cabinet less likely under these electoral rules. Party system
fragmentation is measured as the ENP on the right and left of the parliamentary mean. Most of
our models conﬁrm the impact of party-system fragmentation on the formation of governments.
The greater the fragmentation among right-wing parties, the more the cabinet position moves to
the Left. The evidence for an analogous effect of left fragmentation is even more pronounced.
We ﬁnd that higher fragmentation of either side makes the formation of coalitions more difﬁcult
and leads to a higher share of cabinets at the opposite pole. The party-fragmentation effect
cannot therefore be ascribed to a sole electoral system –it does not clearly discriminate between
majoritarian and PR rules. Yet we had only predicted a shift to the left under PR (Hypothesis 3b).
With respect to our third explanation, we cannot therefore assign the impact of party fragmentation to
In the models we control for the impact of vote-seat share differences (that is, the distance
between the election and the parliament position) on the position of the cabinet (the distance to
the weighted parliamentary mean). Models 1, 5 and 6 conﬁrm a weak impact –if the parliament
is to the right (left) of the electorate then this extends to the formation of a cabinet. Hence we
ﬁnd an effect of electoral systems transmitted to the last element in the chain of delegation:
government formation. A further and independent effect of the electoral system on the cabinet
position cannot be detected (see Table 4, Model 1).
We test the robustness of our estimates using three alternative speciﬁcations of our main models
(1–4). First we check whether our results also hold once we remove two potentially controversial
cases: Ireland and Switzerland (Model 5, Tables 4 and A3). We obtain almost identical results for
the smaller set of countries. We also estimate the main models (1–4) with country-ﬁxed effects
(Model 6, Tables 4 and A4) without our results changing much.
Finally we replicate our models using CMP data (Table A5). When interpreting the results, one
has to bear in mind the divergent scale for our dependent variable, namely the distance between
cabinet and parliament mean, as the CMP left/right estimates run from −100 to 100. The replication
conﬁrms the fragmentation effects –fragmentation of the Right (Left) leads to cabinets that are
further to the left (right) (see Table A5). Yet again this effect is not conﬁned to PR countries and
goes in both directions, left and right. It therefore does not support our third hypothesis with its
exclusive focus on fragmentation of the Right under PR. The same picture emerges if we replicate
the speciﬁcations of Table 4 in a simultaneous equation model (see Table A2).
We can now summarize our ﬁndings. We ﬁnd clear evidence for the ﬁrst two explanations
concerning the impact of electoral rules on government composition, namely the voter-behaviour and
electoral-geography hypotheses. The election position in majoritarian countries is signiﬁcantly
different and to the right of the election position in PR countries. In the process of translating votes
into seats, the parliament mean shifts further to the right in majoritarian systems. We can also conﬁrm
that party fragmentation affects the government composition, but it does so under both electoral rules
and in both directions: the higher the fragmentation of either the Left or the Right, the less likely
these parties are to be in government. Although the fragmentation of parties correlates as expected
with electoral rules (Hypothesis 3a) –with a more fragmented Right in countries with PR electoral
rules –the effects on the formation of governments are not conﬁned to the Right and PR electoral
rules. Hypothesis 3b therefore cannot be conﬁrmed. Finally, we ﬁnd that the disproportionality in the
Impact of Electoral Rules on Elections, Parliaments and Cabinet Formation 13
vote-seat translations, measured as the distance between electoral and parliamentary positions,
extends further to the cabinet level (gap between weighted parliament and cabinet mean). A bias in
the vote-seat translation leads to an additional shift of the cabinet position in the same direction.
One of the most often used explanatory variables in comparative politics and comparative
political economy is ‘Left cabinet share’. With government consumption at 40 to 50 per cent of
GDP in most Western countries, it is of central importance who runs the government. When
asking why the Left is in government more often in some countries than in others, we have
learned that electoral rules systematically affect governments’ideological composition. But how
exactly are electoral rules and the composition of governments connected?
In this study we have tested three mechanisms pertaining to the impact of electoral rules on
the party-political makeup of governments –the voting-behaviour, political-geography and
party-fragmentation hypotheses. We found the ﬁrst two mechanisms at work in the democratic
chain of delegation extending from voting up to the formation of governments. Our ﬁndings
conﬁrm that majoritarian systems have a substantially conservative bias, but that PR systems
present a more nuanced picture.
In light of our results, the overall bias of electoral systems, however, seems to be less
pronounced than previously claimed.
In comparing the post-war democratic governments
(1945–2013) that formed under different electoral systems we can conﬁrm the pattern described
by Iversen and Soskice for majoritarian electoral systems only. Almost two-thirds of all
governments are Right or centre-Right under majoritarian rules, whereas the distribution under PR
shows a much more balanced share of left-wing, centrist and right-wing cabinets
(see Table 3). In majoritarian systems the spatial distribution of votes explains a rightward bias
of the parliamentary mean. This bias is then further enlarged at the cabinet level. The ideological
bent of governments under PR, however, is determined mainly by party fragmentation. Systematic
differences in the fragmentation of the Right or Left help us to better understand the composition
of cabinets, but these differences do not seem to be inevitably linked to electoral rules.
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