A study of learning achievement using pre- and post-unit tests in an ornamental plant production course among vocational certificate students

Abstract

This classroom action research aimed to examine the effects of using pre-tests and post-unit tests on students’ learning achievement and practical skill development in Learning Units 4 and 5 of the Ornamental Plant Production course. The participants were 22 vocational certificate students enrolled in an agricultural program at Ratchaburi College of Agriculture and Technology during the first semester of the 2025 academic year. The research instruments consisted of achievement tests administered before instruction and at the end of each learning unit, as well as a rubric-based practical skill assessment. Content validity of the instruments was verified by three experts using the Index of Item–Objective Congruence, and reliability analysis yielded a Cronbach’s alpha coefficient of .92. Quantitative data were analyzed using paired-samples t-tests to compare pre-test and post-test scores, while descriptive statistics were used to examine students’ practical skill levels. The results revealed that students’ post-test achievement scores in both learning units were significantly higher than their pre-test scores at the .05 level. In addition, most students demonstrated high levels of practical skills, with the majority achieving Very Good to Excellent performance levels. These findings indicate that integrating systematic pre-tests and post-unit tests can effectively enhance learning continuity, reinforce conceptual understanding, and support the development of practical competencies in vocational agricultural education. The instructional approach provides practical implications for teachers seeking to improve formative assessment practices and student-centered learning in similar vocational contexts.