Whether sex differences increase or decrease as more gender equality is achieved remains debatable. Some scholars argue that these differences result from socialization processes and, thus, should diminish when countries progress toward gender equality. Conversely, others predict the opposite pattern, which they refer to as the gender equality paradox. The debate has primarily focused on sex disparities in inorganic science, technology, engineering, and mathematics (STEM) educational fields due to their association with various long-term socioeconomic outcomes, such as the gender pay gap. In fact, despite numerous efforts, women remain underrepresented in these fields—a trend that seems particularly pronounced in more gender-equal countries.
Among the numerous STEM-related factors (e.g., academic skills and personality) proposed to influence this paradoxical trend, intraindividual strengths have recently emerged as a potential critical component. Intraindividual strengths refer to a student’s relative advantage in mathematics, reading, or science compared with their overall scores and independent of peers’ performance. Girls generally perform better in reading than in mathematics or science, while boys generally perform better in mathematics or science than in reading. Sex differences in intraindividual strengths have been linked to career choices in STEM and also appear to follow a pattern consistent with the gender equality paradox.
However, there has not yet been a comprehensive assessment of the gender equality paradox in STEM-related factors, and it remains unclear whether this phenomenon is widespread or specific to a few domains. Moreover, despite their potential relevance, sex differences in intraindividual academic strengths remain largely understudied.
This study aimed to synthesize the literature on the gender equality paradox in STEM-related factors, such as academic skills and personality, to develop a theoretical framework for future research addressing this phenomenon. Additionally, it sought to examine sex differences in intraindividual academic strengths to shed light on the underrepresentation of women in STEM fields.
The research comprised three studies. Following the PRISMA guidelines, Study I involved a systematic review of published scientific literature on STEM-related sex differences in academic skills (in mathematics, reading, and science), as well as personality models (Big Five, HEXACO, basic human values, and vocational interests), and their associations with gender equality indicators. Subsequently, employing data from five recent waves (2006−2018) of the Programme for International Student Assessment (PISA), along with Spearman correlation and ordinary least squares models, Studies II and III investigated how sex differences in intraindividual academic strengths vary with increases in the Global Gender Gap Index (GGGI) from the World Economic Forum—both overall (Study II) and at different levels of academic achievement (bottom 5%, top 5%, and average) (Study III).
The literature review indicates that the gender equality paradox has been extensively studied across many domains and is consistently observed, particularly in personality traits and reading skills. In contrast, sex differences in mathematics appear to emerge regardless of country-level gender equality. Additionally, the review highlighted the potential key role of intraindividual academic strengths in explaining the underrepresentation of women in STEM, although few studies have addressed them. Building on these findings, the results from Studies II and III align with previous research on sex differences in intraindividual strengths. A relative advantage for girls in reading was observed widely across countries and achievement levels, just as a relative advantage for boys was found in mathematics and science. Additionally, the gender equality paradox consistently emerged in sex differences in reading and science as intraindividual strengths, both across PISA waves and achievement levels. In contrast, sex differences in mathematics as intraindividual strengths do not appear to be related to the GGGI.
In the last part of this dissertation, the results are discussed in the context of expectancy-value theory, which posits that intraindividual strengths should influence future career choices. On this premise, limitations are addressed, and recommendations are proposed for future research as well as new policies aimed at reducing the underrepresentation of women in STEM.