VALUES AND ACHIEVEMENT AMONG GIRLS: A
COMPARATIVE ANALYSIS IN SINGLE-SEX VS. CO-
EDUCATIONAL SETTINGS USING TIMSS 2019 NZ DATA
Huayu Gao, Tanya Evans & Gavin T. L. Brown
University of Auckland, New Zealand
Grounded in the Social Cognitive Career Theory, this study investigates the influence
of values on girls' mathematics achievement across socio-economic status (SES)
settings, contrasting single-sex and co-educational schools. ANOVA on 2019 TIMSS
New Zealand data (n = 2,898) reveals that single-sex education is associated with
enhanced girls' mathematical values in high-SES settings. However, its effect on
translating these values into improved mathematics performance is relatively limited.
Affluent learning resources are the more immediate factor in improving mathematics
performance. Moreover, in low-SES environments, the relation between values and
mathematics achievement exhibits a complex nonlinear pattern.
INTRODUCTION
In most OECD countries, including New Zealand, the proportion of female graduates
in traditionally male-dominated fields of Science, Technology, Engineering, and
Mathematics (STEM) in higher education is significantly lower than that of males, with
an average of only 33% (OECD, 2023). This gender segregation trend extends to the
occupational domain. For instance, a New Zealand government report indicates that
only 27% of digital technology positions are held by women (Hindle & Muller, 2021).
Academia faces similar challenges; according to data from the University of Auckland
(NZ), the distribution of female faculty ranks in the Faculty of Science and Engineering
is significantly lower than that of males, particularly in engineering, where the gap is
most prominent (Brower & James, 2020). Without effective interventions, this gender
imbalance is projected to persist until 2070 (Brower & James, 2020).
Girls in some Islamic countries exhibit a notable advantage in math achievement,
values, and career aspirations for math-intensive careers, which stands in stark contrast
to the gender difference trends observed in most Western regions (Michaelides et al.,
2019). This phenomenon may be attributed to the unique social circumstances faced
by women in these Islamic countries. Women's social status is relatively low in many
Islamic nations, while careers in STEM fields often offer higher salaries.
Consequently, girls may aspire to excel in mathematics and subsequently pursue high-
paying math-related careers as a means to elevate their social standing (Stoet et al.,
2018). This observation suggests that among the female population, there may be a
significant association between value, mathematics performance, and the likelihood of
1 - 275
2025. In C. Cornejo, P. Felmer, D. M. Gómez, P. Dartnell, P. Araya, A. Peri, & V. Randolph (Eds.). Proceedings of the
48th Conference of the International Group for the Psychology of Mathematics Education: Research Reports, Vol. 1,
pp. 275-282. PME.
, Gao, Evans, Brown
entering math-intensive fields. From this perspective, girls' values and achievements
could serve as ideal entry points for investigating their propensity to pursue math-
related careers.
Apart from social factors, the single-sex education widely adopted in these Islamic
countries—where girls attend all-girls schools taught by female teachers and boys
attend all-boys schools taught by male teachers (Michaelides et al., 2019)—may also
contribute to girls' mathematics achievement to a certain extent. However, when
examining the impact of single-sex education on girls' mathematics performance, it is
crucial not to overlook the significant role of students' socioeconomic status (SES).
SES is considered the most influential factor affecting students' mathematics
achievement, accounting for more than 50% of the variance in girls’ mathematics
performance (Gao et al., 2025). Relevant research indicates that when SES is not
controlled for, gender differences in mathematics achievement exist; however, when
SES is controlled for, these gender differences significantly narrow or disappear
(Clavel & Flannery, 2023). Therefore, to more accurately assess the effectiveness of
single-sex education, it is necessary to consider and control for the SES. Smith and
Evans' (2023) study in New Zealand serves as an excellent example. After controlling
for students' SES, they found that girls from low SES families in single-sex schools
outperformed girls attending co-educational schools in mathematics (g = 0.90), further
supporting the potential advantages of single-sex education.
New Zealand's education system offers a distinctive setting for investigating the effects
of single-sex schools. Among the 374 secondary schools in NZ, approximately 16%
are single-sex girls' schools, with a striking 91% of these institutions being state or
state-integrated schools (MoE, 2023). This contrasts sharply with the United States and
Australia, where single-sex schooling is primarily concentrated in private or Catholic
schools. Furthermore, New Zealand employs a decile system to measure the
socioeconomic background of schools. This system ranks schools from 1 to 10, with
decile 1 representing schools whose students come from the lowest 10% of families
and decile 10 representing schools whose students come from the highest 10% of
families.
THEORETICAL BACKGROUND
The performance model of the Social Cognitive Career Theory (SCCT) provides a
comprehensive framework for understanding the interplay between individual
motivation and environmental factors in shaping math-related performance (Lent &
Brown, 1994). More specifically, the model centers on the core constructs of self-
efficacy and outcome expectation, which dynamically interact with person factors,
contextual influences, and learning experiences to collectively shape academic
outcomes. Outcome expectations, as a center component, encompass the concept of
values, reflecting individuals' preferences for the "reinforcers" of academic activities
(Dawis & Lofquist, 1984). For instance, mathematical values are not only embodied in
the interest in mathematics itself but also include the expectation that learning
1 - 276 PME 48 – 2025