the main intervention. The experimental design was based upon the Solomon Four-

Group Design (Solomon, 1949). This design was selected to investigate the main

intervention effect while controlling for the effect of the pretest or the time between the

pretest and the posttest (Creswell, 2002; Trochim, 2001; Van Engelenburg, 1999).

Volunteer participants who created online accounts were randomly assigned by the

system into one of four groups. The first group completed the Career Decision Scale

(CDS) as a pretest, the online intervention, and the CDS as a posttest. The second group

completed the online intervention and the CDS as posttest only. The third group

completed the CDS pretest followed by the CDS posttest after a two-week waiting period

(with no intervention). Finally, the fourth group completed only the CDS posttest. The

design was selected to help determine if the intervention influenced Career Certainty and

Career Indecision (as measured by the CDS subscales) while removing the testing threats

presented by protests and posttests. This design is represented in Table 1.


Table 1 : Project Solomon Four-Group Design
 Online
Group One CDS neeni CDS Questionnaire
 Intervention
 Online
Group Two neeni CDS Questionnaire
 Intervention
Group Three CDS Time Delay CDS

Group Four CDS


 Therefore, there were four possible outcomes of the study: a treatment effect with

no testing effect, treatment and testing effects, a testing effect and no treatment effect, or

no effect. To be more specific, first, the online intervention could have impacted

participants' scores on the Career Decision Scale (CDS) independent of any effects from

the pretest. Second, the CDS pretest could impact participants' scores on the CDS

independent of any effects from the intervention. Third, both impacts might have