The increasing use of low-stakes international assessments highlights the importance of test-taking efforts. Previous studies have used self-reported and response time-based measures to examine this effort. Although differences between these measures have been suggested, their association with performances and potential gender gaps remains underexplored. This study addresses this gap by using PISA 2022 data from 20,560 Canadian students (50% female) with polynomial regression and response surface analysis. Findings revealed that the congruence and discrepancy between self-reported effort (SRE) and response behaviour effort (RBE) significantly affect test achievements. Students showing high levels in both efforts achieved the highest scores, with congruence outperforming discrepancy. When discrepancies exist, students with higher RBE outperformed those with higher SRE. Gender differences emerged, with RBE having a significantly stronger impact on males' math and SRE having a slightly greater effect on females' reading. These findings offer new insights into effort and gender gaps in educational assessments.