Available Cases Figures 18 and 19 display the number of cases and percent of the study sample that had assess- ment data available for the alcohol and drug SOCRATES forms, respectively. There were 66 (51%) of the 129 participants who had initial SOCRATES assessments using the alcohol form, with 51 (39%) and 19 (15%) having second and third assessments available, respectively. There were 119 (92%) of the 129 participants who had initial SOCRATES assessments using the drug form, with 25 (19%) having a fifth assessment available. Considering the relationship between sample size and statistical power (Cohen, 1988), which is more generous when using repeated measures approaches to analyses (Stevens, 1996), the analyses using the alcohol form included the first three assessments and those using the drug form included the first five assessments.
Figure 18 Number of cases and percent of the study sample with SOCRATES alcohol assessment data available
S OC RAT E S Alco ho l Assessment D ata: P articip ants O ver T im e
A s s e s s m e n t T im e
P c t o f S a m p le
Figure 19 Number of cases and percent of the study sample with SOCRATES drug assessment data available
Idaho Pre-Treatment Program