HOME-STUDY DRIVER EDUCATION
This finding supports the concurrent validity of the exit test, given that both this test and the DMV written test overlap in some of the knowledge areas covered. The fact that none of the other outcome measures were correlated (ps > .05) suggests that they are indeed measuring different things. The somewhat surprising, although not statistically significant, negative correlation between DMV written and drive test outcomes is a result of the fact that of the 61 persons for whom a drive test outcome was available, only 5 (8.2%) passed the drive test on their first attempt, whereas 50 (82.0%) passed the written test on their first attempt. The very low variance in the drive test pass rates would tend to make any correlation with this outcome low and very unstable.
For the 721 study students included in the DMV written test comparisons, 479 (66.4%) passed the written test on their first attempt, which is about 15% higher than the 51.7% first-attempt pass rate for California teens in general, based on a recent evaluation by Chapman and Masten (2002). Given that the study pass rate reflects only students who did not enroll in driver training, and hence completed driver education before attempting their first DMV written test, the higher pass rate for study students probably indicates that completing driver education increases the likelihood that students will pass the DMV written test on their first attempt.
Time to Complete Each Course
For the 1,200 students who had valid course assignment and exit exam dates, the median number of days to course completion was calculated for each instruction method. The median number of days the students required to complete their study driver education course was 14 for classroom instruction, 49 for PEN, 30 for the CD program, and 31 for the workbook course. The higher median number of days for PEN students is surprising given that PEN charged additional fees to their students if the course was not completed within 30 days of issuance.
Exit Exam Knowledge Comparisons
For each of the statistical comparisons, Table 4 presents the sample sizes, mean exit exam knowledge scores, and standard deviations for each instructional method. The relationship among the exit exam knowledge means is illustrated in Figure 1. Table 5 presents results of the ANOVA for each of the six different statistical comparisons (Overall, Correctly Assigned, Driver Training, No Driver Training, Computer, and No Computer) and also the difference between the exit exam scores for the home-study and classroom courses. These mean differences were calculated by subtracting the classroom mean knowledge score from each home-study instructional method mean knowledge score. Hence, a negative mean difference indicates that classroom students had a higher mean level of knowledge on the exit exam, while a positive mean difference indicates that students in the home-study program had a higher mean