EVIDENCE BASED PRACTICE 2 Evidence Based Practice in Career and Workforce Development Interventions This chapter summaries the scientific foundation for career and workforce development interventions with the intent of providing insight into what constitutes evidence-based career interventions. Spokane and Oliver (1983) defined vocational interventions as any treatment or effort intended to enhance an individual's career development or to enable the person to make better career-related decisions. We have a similar definition of career and workforce development interventions, which is any treatment or effort intended to enhance an individual's career, occupational, or work-related development or to enable the person to make better workrelated decisions, and help them managing their work transitions. This is a broad definition that encompasses a wide array of interventions, such as individual counseling, group activities, career classes, computer information systems, and self-help interventions. Consistent with the other chapters in this book, we use the labels of promising, evidence informed, and evidence based to categorize the evidence and to classify the interventions. See Chapter ? for the operational definitions of these demarcations.
Evidence for Career InterventionsIn essence, we are asking the question: are career interventions effective? In order to address whether career intervention are effective, we are going to first explore the long history of meta-analyses on career interventions. These meta-analyses provide important information about the overall effectiveness of career and workforce development interventions. Metaanalytic studies combine the results of studies to produce average effect sizes. In the career area, all of the meta-analyses have collated the findings from treatment versus control comparisons.In these meta-analyses, the mean of the control group is subtracted from the mean of the experimental group which is divided by the pooled standard deviation of the two groups, which EVIDENCE BASED PRACTICE 3 produces an effect size. The effect sizes are typically weighted by sample size and the inverse variance and combined to produce an average effect size. The first meta-analysis conducted was by Spokane and Oliver (1983) and was later incorporated into a more comprehensive analysis by Oliver and Spokane (1988). Oliver and Spokane (1988) analyzed 58 studies, involving 7,311 participants, which produced an unweighted effect size of .82. Using a more sophisticated weighting system and more recent research, Whiston, Sexton, and Lasoff (1998) found an average of effect size of .30. This effect size was based on 47 studies involving 4,660 participants. Using a similar weighting strategy to Whiston et al., Brown and Ryan Krane (2000) found an average effect size of .34 based on 62 studies and 7,725.As reflected above, the average effect sizes for career interventions ranged from .30 to .82. The effect size of .82 found by Oliver and Spokane is somewhat of an outlier because it is not weighted; how...