Construct Validity of Assessing Interest in STEM Content Scale

The purpose of this research was to validate the assessing interest in STEM content scale. The sample in this research was 552 students in upper secondary school at Fangchanupathum School, Chiang Mai, Thailand, who validated the assessing interest in STEM content scale, which used a rating scale of four factors consisting of (1) science, (2) mathematics, (3) laboratorial skills, and (4) technology and 20 items. Confirmatory factor analysis was used to confirm the construct validity of the assessing interest in STEM content scale adapted from the study by Tyler-Wood, Knezek, and Christensen. The results confirmed that the construct validity of this assessing interest in STEM content scale had an excellent fit. They showed that the fitness index of validating the assessing interest in STEM content scale was X2 statistic of 163.679 (degree of freedom = 141, P value = 0.0928) and the X2 /df ratio having a value of 1.160 indicating a good fit. The comparative fit index (CFI) was 0.991, and Tucker–Lewis coefficient (TLI) was 0.988. The root mean square error approximation (RMSEA) was 0.017. The standardized root mean residual (SRMR) was 0.047. All the indicators indicated that there was a good fit between the empirical data and the hypothetical measurement model.