Abstract:
The purposes of this research were to 1) develop the students writing skills by using B-SLIM Model for the fourth graders and study the efficiency of the writing drills based on the efficiency criteria of 80/80, 2) to compare the students writing skills before and after using the drills by using B-SLIM Model. The sample consisted of 30 fourth graders studying in the second semester of academic year 2020 at Bansangming School and Bannakhamdonteaw School, gained by cluster sampling. The research instruments were the drills by using B-SLIM Model and a writing test made by the researcher, the test had the difficulty indices between .44-.59, the discrimination indices between .23-.95, and the reliability of .90. The statistics used for data analysis was mean, percentage, standard deviation, and t-test.
The research findings were as follows:
1. The students had the writing skills at the level of good, with the mean score of 24.63, which was at 82.11 percent, the developed drills by using B-SLIM Model had efficiency values of 87.57/82.11, based on the standardized criteria of 80/80.
2. The students writing skills after using the developed drills was significantly higher than that before using them at the .01 level.