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Journal of Quality Measurement and Analysis JQMA 17(1) 2021, 49-59
e-ISSN: 2600-8602 http://www.ukm.my/jqma
ANALYSIS OF GENDER INCOME GAP IN MALAYSIA
(Analisis Jurang Pendapatan antara Jantina di Malaysia)
NURFATIN IRDINA MUHAMMAD NAJIB & NORIZA MAJID*
ABSTRACT
The participation of women in the Malaysian labour market has shown a significant increase
over the years. However, compared to the male labour force participation rate, the female labour
force participation rate is still at a low level. Various efforts have been made by the government
to ensure gender equality in the economic sector, however, there is still discrimination against
women in the workplace. One of them is the income gap between male and female workers.
This study aims to analyse the gender income gap in Malaysia and identify the factors that
contribute to the income gap. This study utilises two models, namely multiple linear regression
model and Blinder-Oaxaca income decomposition model. Data were obtained from the Salaries
& Wages Survey in 2016. Multiple linear regression model is used to estimate the influence of
demographic and human capital factors on employee income levels. The Blinder-Oaxaca
income decomposition model is used to analyse gender income differences. The results of the
study found that the income of female workers, on average, is lower than that of male workers.
The study also shows that education plays an important role in determining the gender income
gap. In addition, the income decomposition model suggests that the big gap in the gender income
is contributed by unexplained factors, which refer to discrimination.
Keywords: gender discrimination; income decomposition; labour market
ABSTRAK
Penyertaan wanita dalam pasaran tenaga buruh di Malaysia telah menunjukkan peningkatan
yang signifikan dari tahun ke tahun. Namun jika dibandingkan dengan kadar penyertaan tenaga
buruh lelaki, kadar penyertaan tenaga buruh perempuan masih lagi berada pada tahap yang
rendah. Pelbagai usaha telah dilakukan oleh pihak kerajaan untuk memastikan kesaksamaan
jantina dalam sektor ekonomi, namun masih wujud diskriminasi terhadap perempuan di tempat
kerja. Satu daripadanya adalah jurang pendapatan antara pekerja lelaki dan perempuan. Kajian
ini bertujuan untuk menganalisis jurang pendapatan jantina di Malaysia dan mengenal pasti
faktor yang menyumbang kepada jurang pendapatan berkenaan. Kajian ini menggunakan dua
model, iaitu model regresi linear berganda dan model pengasingan pendapatan Blinder-Oaxaca.
Data diperoleh daripada Survei Gaji & Upah pada tahun 2016. Model regresi linear berganda
digunakan untuk menganggar pengaruh faktor demografi dan modal insan terhadap aras
pendapatan pekerja. Model pengasingan pendapatan Blinder-Oaxaca pula digunakan untuk
menganalisis perbezaan pendapatan berdasarkan jantina. Hasil kajian mendapati pendapatan
pekerja perempuan, secara purata, adalah lebih rendah berbanding dengan pekerja lelaki. Kajian
ini juga menunjukkan bahawa pendidikan memainkan peranan penting dalam menentukan
jurang pendapatan berdasarkan jantina. Di samping itu, model pengasingan pendapatan
menunjukkan bahawa sebahagian besar jurang pendapatan jantina disumbangkan oleh faktor
yang tidak dapat dijelaskan, yang merujuk kepada diskriminasi.
Kata kunci: diskriminasi jantina; penguraian pendapatan; pasaran buruh
Nurfatin Irdina Muhammad Najib & Noriza Majid
50
1. Introduction
The Malaysian labour market has seen positive changes since independence, in line with its
economic growth. The Economic Outlook 2020 Report shows that the total labour force in the
first half of 2019 increased by 2.2% to 15.5 million labour force (Ministry of Finance Malaysia
2019). The increase in labour force indicates that Malaysian labour market is in favourable
condition. Alongside the increase in the labour force, women’s labour force participation rate
had also increased to 54.1% in 2015. However, men’s labour force participation rate (80.6%)
remains higher than women’s in 2015. The gap is not only evident in the labour force
participation rate but also in earned incomes. According to Selamat (2009), the gender income
gap persists, although both men and women do similar jobs. If this situation continues, the
labour market will cripple due to dissatisfaction among women employees, resulting in them
leaving the labour market and not contributing their skills optimally (Ismail et al. 2013).
Table 1 shows the Malaysia Gender Gap Index (MGGI) scores for 12 years. MGGI identifies
the gap between men and women across four sub-indices encompassing Economic Participation
and Opportunity, Educational Attainment, Health and Survival, and Political Empowerment. A
score of 1.0 (100%) indicates that gender equality has been achieved. Overall, the MGGI
increase slowly from 2006 to 2017. This suggests that gender inequality still exists with a 33%
gap between men and women in 2017. Similarly, the Economic Participation and Opportunity
sub-indices show a positive change from 2006 to 2017 with a score of 0.59 and 0.65,
respectively.
Table 1: MGGI by year and score
Year
Overall
Economic Participation and Opportunity
2006
0.65
0.59
0.57
2007
0.64
2008
0.64
0.56
2009
0.65
0.56
2010
0.65
0.58
2011
0.65
0.59
2012
0.65
0.60
2013
0.65
0.59
2014
0.65
0.62
2015
0.65
0.63
2016
0.67
0.66
2017
0.67
0.65
Source: Malaysian Open Data Portal (2018).
The Blinder-Oaxaca income decomposition method was used in many studies to analyse the
gender income gap (Deshpande et al. 2018; Fernandez 2009; Ismail et al. 2013). Multiple linear
regression and Blinder-Oaxaca income decomposition method were used in this study to
analyse the gender income gap in Malaysia further. Past studies suggested many factors
contribute to the gender income gap including occupational segregation, women’s
responsibility towards family, gender discrimination and human capital (Blau & Kahn 2017;
Chapman & Harding 1985; Fernandez 2009; Ismail & Jajri 2012; Zainol Abidin et al. 2016).
The study aims to analyse the Malaysian gender income gap and identify the factors
contributing to the gender income gap. Five variables used in this study were employee’s
monthly income, gender, age, marital status and education level. This research information is
expected to help the government devise strategies to boost women’s economy and ensure
gender equality in Malaysia.
Analysis of gender income gap in Malaysia
51
2. Materials and Method
Salaries & Wages Survey 2016 data conducted by Department of Statistics Malaysia, consisting
of 13,089 samples were obtained from The National University of Malaysia (UKM) Bank Data.
Data obtained contains information on workers’ demographic factors, education background
and their industries. Table 2 represents the distribution of education level and marital status by
gender. Almost 60% of the sample were male, and the rest were female. Overall, the majority
of the workers obtained a secondary education and above. The proportion of male who obtained
secondary education is higher than female. However, more females obtained tertiary education
than males.
Table 2: Education level and marital status by gender
Variables
Male
Female
Total
Number
%
Number
%
Number
%
Education level
No education
78
0.60
55
0.42
133
1.02
Primary
691
5.28
257
1.96
948
7.24
Secondary
4846
37.02
2543
19.43
7389
56.45
Tertiary
2226
17.01
2393
18.28
4619
35.29
Marital status
Single
2615
19.98
1742
13.31
4357
33.29
Married
5226
39.93
3506
26.79
8732
66.71
Total
7841
59.91
5248
40.1
13089
100.0
2.1. Multiple linear regression model
Multiple linear regression was used to estimate the effect of demographic factors and human
capital, in this case refers to education level, on workers’ income level. This model consists of
three income equation: (1) using the pooled sample, (2) male sample and (3) female sample.
The regression model for workers’ monthly income used is as follows:
(1)
where W is monthly income,
X
represents a vector of demographic variables,
Z
represents a
vector of human capital variables and
is the error term. The existence of this error may be due
to the effect of other variables not included in the model.
By incorporating the estimates into Eq. (1), the estimated income equation for pooled, male
and female sample are as follows:
(2)
(3)
(4)
Nurfatin Irdina Muhammad Najib & Noriza Majid
52
where W is monthly income,
i0 is the intercept, AGE is age, GEN is gender, EDUi1, EDUi2 and
EDUi3 are dummy variable for primary education, secondary education and tertiary education
respectively,
is the error term, M and F are male and female, respectively.
2.1.1. Model evaluation
The multiple linear regression model must satisfy normality, linearity and reliability
assumptions to ensure analysis accuracy. Evaluation of the fitness of the model is as follows:
(1) The coefficient of determination, R2
The coefficient of determination, R2 is used to determine the independent variables’
contribution to the variance in the dependent variable. Values of R2 that are close to 1 imply
that most of the variability in worker’s monthly income is explained by the regression model
(Montgomery et al. 2012). R2 is defined as below:
(5)
Enter regression procedure was used to determine each independent variable’s relative
contribution to the log of monthly income. Table 3 shows the enter regression procedure.
Table 3: Independent variables for each model
Model
Independent variables
1
Age
2
Age, marital status
3
Age, marital status, education level
4
Age, marital status, education level, gender
(2) F-test
This test was used to test for regression’s significance by identifying the linear relationship
between the dependent variable and any of the independent variables (Montgomery et al. 2012).
The hypothesis used in this test is as follows:
Rejection of null hypothesis shows that linear relationship exists between the dependent
variable and at least one independent variable. F-statistic is defined as below:
(6)
Analysis of gender income gap in Malaysia
53
where n is data count, k is the degree of freedom, the sum of squares due to regression and
error sum of squares are as follows:
If the p-value is less than the significance level, then the null hypothesis is rejected.
(3) t-test
This test was used to test for the significance of the independent variable in determining the
independent variable. (Montgomery et al. 2012). The hypothesis used in this test is as follows:
Rejection of the null hypothesis implies that the independent variable is significant in
determining the log of worker’s monthly income. t-statistic is defined as below:
(7)
where
ˆi
se
is the standard error of the independent variable. If the p-value is less than the
significance level, then the null hypothesis is rejected.
(4) Multicollinearity
Multicollinearity is a problem when the independent variables have a high correlation with each
other or have near-linear relationships. Multicollinearity can be detected by looking at the
variance inflation factors (VIF) that are defined as follows:
A VIF value around 5 to 10 implies that multicollinearity exists (Montgomery et al. 2012).
2.2. Blinder-Oaxaca income decomposition model
The income decomposition model used in this study was built by Blinder (1973) and Oaxaca
(1973). This model divides the income differentials into two parts. The first part refers to the
income differentials due to differences in productivity characteristic, including human capital.
The second part refers to unexplained income differentials, which often used as a measure for
discrimination.
Nurfatin Irdina Muhammad Najib & Noriza Majid
54
This study used Neumark (1988) approach in building the Blinder-Oaxaca income
decomposition model, which uses the pooled sample’s coefficient as non-discriminatory
coefficients. Therefore, the mean gender income differentials can be written as follows:
(8)
where
ˆ
ln ,ln , , ,
M F M F M
W W X X
and
ˆF
are the mean of the natural logarithm of the
observed monthly incomes, the mean of the observed productivity characteristics and the
coefficient estimates for females and males respectively.
*
ˆ
is the coefficient estimates
obtained from the pooled sample estimates. The first term on the right-hand side of Eq. (8)
represents the explained part of income differentials, while the last two terms represent the
income differentials’ unexplained part.
3. Results and Discussions
3.1. Model evaluation
(1) The coefficient of determination, R2
Table 4 reports the R2 values for each model from the enter regression procedure. The difference
in R2 value refers to the relative contribution of the independent variable to the log of monthly
income. Based on Table 4, model 3 and 4 is the best model in estimating the income equation
for the male and female sample and the pooled sample, respectively. For all income equation,
almost 30% of the variability in the log of monthly income can be explained by education level,
holding other independent variable constant.
Table 4: R2 value for enter regression procedure
Pooled
Male
Female
Model
R2
R2 difference
R2
R2 difference
R2
R2 difference
1
0.0851a
-
0.1049a
-
0.0571a
-
2
0.1075b
0.0224
0.1418b
0.0369
0.0665b
0.0094
3
0.4073c
0.2998
0.4051c
0.2633
0.4579c
0.3914
4
0.4245d
0.0172
-
-
-
-
Note: a Regressor: (constant), age.
b Regressor: (constant), age, marital status.
c Regressor: (constant), age, marital status, education level.
d Regressor: (constant), age, marital status, education level, gender.
(1) F-test
Table 5 summarises the F-statistic for the pooled sample, male sample and female sample
income equation. The p-value for all income equations model are less than the significance
level, 0.05. This demonstrates that at least one of the independent variables is significant to the
model.
Analysis of gender income gap in Malaysia
55
Table 5: Summary of F-statistic
Pooled
Male
Female
F
1608.55
1067.28
885.50
p-value
0.000
0.000
0.000
(2) t-test
The coefficients and p-value of all independent variables are shown in Table 6. The p-value for
all independent variables in the three income equations are significant at 1% except for the
education level variable in the male sample income equation, which is significant at 10%. This
shows that all independent variables are significant in determining the log of monthly income.
Table 6: Coefficients and p-values of variables
Variables
Pooled
Male
Female
Coefficients
p-value
Coefficients
p-value
Coefficients
p-value
Gender
-0.190***
0.000
Age
0.018***
0.000
0.016***
0.000
0.020***
0.000
Marital status (married)
0.1930**
0.000
0.255***
0.000
0.113***
0.000
Education level
Primary
0.221***
0.000
0.144*
0.022
0.281***
0.000
Secondary
0.651***
0.000
0.534***
0.000
0.822***
0.000
Tertiary
1.392***
0.000
1.212***
0.000
1.634***
0.000
Constant
6.173***
0.000
6.126***
0.000
5.570***
0.000
Note: ‘ * ’ – significant at 10% ‘ *** ’ – significant at 1%
(3) Multicollinearity
Table 7 reports the VIF of all independent variables for the three income equations. The
secondary and tertiary education variable have VIF value above 10, indicating that the model
has a multicollinearity problem. According to Allison (2012), the multicollinearity can be
ignored because the variable is an indicator dummy variable which proportion of cases in the
reference category is small.
Table 7: VIF of independent variables
Variables
Pooled
Male
Female
Gender
1.04
-
-
Age
1.50
1.54
1.44
Marital status (married
1.44
1.50
1.37
Education level
Primary
7.55
8.99
5.41
Secondary
24.84
24.18
24.95
Tertiary
23.35
21.22
24.86
Nurfatin Irdina Muhammad Najib & Noriza Majid
56
3.2. Results of regression estimates
Table 8 reports ordinary least square (OLS) estimates for the three income equations: (1) using
the pooled sample, (2) male sample and (3) female sample. The results demonstrate that all
incorporated variables are positive and significantly determine the natural log of income. Based
on the coefficient of determination, R2 for all income equations, more than 40% of the
dependent variable’s variation can be explained by independent variables, consistent with past
studies by Ismail and Jajri (2012) and Ismail et al. (2013).
Based on the coefficient values, the pooled sample, male sample and female sample income
equation are as follows:
(9)
(10)
. (11)
Since the equation is in log form, the percentage change of independent variable towards the
percentage change of income can be calculated using the following formula:
(12)
where
i
X
is the coefficient value of the independent variable.
Based on the pooled sample income equation analysis, an increase in one unit (one year) age
will only increase the worker's income up to 2%. Worker’s income level will also increase up
to 20% if the worker is male or married. Returns to education increases as education level
increases. This finding is coherent with past studies about the relationship between human
capital and workers' income (García-Aracil 2007; Ismail & Jajri 2012).
By incorporating the coefficient value of male’s and female’s marital status in Eq. (12), it is
shown that married male workers receive higher income premiums, which is 29% compared to
11.96% income premiums received by married female workers. In contrast, each education
level demonstrates that female workers' education return is twice their male counterparts. This
result is also consistent with past studies (Ismail & Jajri 2012; Ismail et al. 2013; Papapetrou
2004).
Analysis of gender income gap in Malaysia
57
Table 8: Results of regression estimates
Variables
Pooled
Male
Female
Coefficient (t-value)
Coefficient (t-value)
Coefficient (t-value)
Demography
Age
0.018
(34.96) ***
0.016
(25.43) ***
0.020
(24.12) ***
Gender
0.190
(19.81) ***
-
-
Marital status
(married)
0.193
(16.37) ***
0.255
(16.61) ***
0.113
(6.16) ***
Human capital
Education level
Primary
0.221
0.144
0.281
(4.51) ***
(2.30) *
(3.55) ***
Secondary
0.651
(14.01) ***
0.534
(8.93) ***
0.822
(11.20) ***
Tertiary
1.392
(29.77) ***
1.212
(20.08) ***
1.633
(22.21) ***
Constant
5.792
(115.59) ***
6.126
(96.66) ***
5.570
(69.14) ***
N
13089
7841
5248
R2
0.4245
0.4051
0.4579
Note: ‘ * ’ – significant at 10% ‘ ** ’ – significant at 5% ‘ *** ’ – significant at 1%
3.3. Results of income decomposition model
Table 9 illustrates the decomposition of gender income differentials divided into the explained
and unexplained part. Overall, the mean monthly income among male workers is higher, with
7.584 log points than their female counterparts, 7.512 log points. The difference demonstrates
that males earn 7.4% higher than females. However, the unexplained part in the income
differentials gives negative value, which is -0.119 log points. This indicates that if female were
to be paid for the same characteristics as male, they would earn higher than males. The estimate
of income gap is lower than Maczulskij and Nyblom (2020), who examined the Finnish gender
wage gap and found that males receive 16% higher wages than females.
The unexplained part of the income differentials is 0.190 log points, which is bigger than
the gender income differentials itself. According to Becker (1971), the unexplained portion of
income differentials may represent discrimination. Thus, this finding suggests that income
discrimination exists in the Malaysian labour market, affecting females.
Based on Table 9, education level contributes negatively to the total differentials. This
indicates that education could bridge the gender income gap, consistent with Ismail and Jajri
(2012). A significant portion of the unexplained part is contributed by the worker’s marital
status. The results show that married male workers earn higher than females of the same status.
This suggests that married women may encounter a motherhood penalty in the workplace,
coherent with Takenoshita (2020).
Nurfatin Irdina Muhammad Najib & Noriza Majid
58
Table 9: Results of income decomposition model
Variables
Explained
Unexplained
Total
*
ˆ
MF
XX
**
ˆ ˆ ˆ ˆ
M M F F
XX
ln ln
MF
WW
Age
0.0258
-0.134
-0.108
(-21.68)
(-70.53)
(-150.42)
Marital status
-0.000303
0.0238
0.0238
(0.255)
(12.53)
(33.15)
Education level
-0.144
-0.114
-0.258
(121.0)
(-60.0)
(-359.33)
Constant
-
0.415
0.415
(218.42)
(577.99)
Total
-0.119
0.190
0.0718
(100.0)
(100.0)
(100.0)
Overall
Male
7.584
Female
7.512
Difference
0.0718
Explained
-0.119
Unexplained
0.190
Note: Figures in parentheses are the percentage of total differentials calculated by dividing
each variable coefficient by their respective total.
4. Conclusion
This study aims to analyse the Malaysian gender income gap and identify the factors
contributing to the income gap. Factors including gender, age, marital status and education level
were included in the analysis to examine the extent of the gender income gap using multiple
linear regression and the Blinder-Oaxaca income decomposition model. The results of this
study show that the gender income gap exists in the Malaysian labour market. Male workers,
on average, earn higher than their female counterparts. A large portion of the gender income
gap is unexplained, indicating that income discrimination exists. The results are also consistent
with Papapetrou (2004) in Greece and Sukma and Kadir (2019) in Indonesia, which showed
that about 60% and 70% of the gender income gap, were unexplained.
The results also reveal that income discrimination was attributed to workers’ marital status
that is often affecting women. This is partly due to the motherhood penalty and employer’s
perception towards women, resulting from gendered norm and expectations (Miller & Vagins
2018). In contrast, the negative relationship between education level and the gender income gap
demonstrates that education could bridge the income gap between male and female.
Overall, the gender income gap problem could give a negative impact on the Malaysian
labour market. Discriminatory factors must be taken into account in labour legislation to ensure
gender equality. A study found that a change in labour legislation that requires firms to provide
gender-disaggregated wage statistics reduces the gender pay gap in Denmark by approximately
2% (Bennedsen et al. 2019). A non-discriminatory labour market could ensure a country’s
development is at its optimum level since both men and women could contribute actively to the
economy.
Analysis of gender income gap in Malaysia
59
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School of Mathematical Sciences
Faculty of Science and Technology
Universiti Kebangsaan Malaysia
43600 UKM Bangi
Selangor DE, MALAYSIA
E-mail: fatin.irdina31@gmail.com, nm@ukm.edu.my*
Received: 6 April 2021
Accepted: 15 June 2021
*Corresponding author
