Development of Basic Biotechnology Knowledge Scale (BBKS) with Rasch Measurement Model

Abstract

The purpose of this study was to develop a scale to measure basic biotechnology knowledge, examine the psychometric properties of the scale, and investigate whether there are differences in the test performances of high school students in terms of school, grade, and gender. The development phase of this scale was carried out with a sample of 388 high school students in a province in the west of Turkey. The psychometric properties of the scale were examined using the Rasch model. The K-R internal consistency coefficient of the final scale consisting of 17 items was calculated as 0.77. It was observed that item-total correlations varied between 0.25 and 0.48 except for one item (item 1, 0.13). The results of the Rasch analysis indicated that the scale fits the Rasch model and can differentiate low and high performing test takers. Three-Way ANOVA results demonstrated a significant main effect for the school. There were no statistically significant differences for grade and gender variables in terms of their biotechnology knowledge scores. However, the grade*gender interaction was statistically significant favoring males with small effect size. This observed effect was possibly due to uneven sample size of 12th grade students. The overall results suggest that the Basic Biotechnology Knowledge Scale (BBKS) can be used to assess the knowledge level of high school students.