Determining the differences in the ability of Iranian students based on their response styles in the TIMSS Grade 8 science test (2011, 2015, and 2019)

Abstract

The present study aimed to identify the differences in the ability of Iranian students based on their response styles in the TIMSS (Trends in International Mathematics and Science Study) Grade 8 science test for the years 2011, 2015, and 2019. This study examined various response styles, including extreme, moderate, and acquiescent styles, as well as their effects on item psychometric parameters and individual abilities. Data were analyzed using various Item Response Theory (IRT) models. The results showed that in the 2011 TIMSS Grade 8 science test, individuals with a typical response style exhibited the highest ability, followed by those with a moderate response style. The lowest ability was observed among individuals with an acquiescent response style. In the 2015 TIMSS Grade 8 science test, individuals with an extreme response style had the highest average ability among all groups, suggesting their superior ability compared to other individuals. Furthermore, in the 2019 TIMSS Grade 8 science test, there was no significant difference in the abilities of individuals with a moderate response style and those with an acquiescent response style (P > 0.05). However, a statistically significant difference was found between the abilities of individuals with an extreme response style and those of other groups (P < 0.05). A statistically significant difference was also observed between the abilities of individuals with a typical response style and those with an acquiescent response style. These findings can contribute to the improvement of standardized test design, reduction of cultural biases, and provision of strategies for more accurate assessments at both national and international levels.