The assessment of clinical significance is an important aspect of behavioral intervention research. Measures of clinical significance should be included in the evaluation of intervention programs, especially at the later phases of the pipeline (efficacy, effectiveness, translation/implementation studies). Evaluation of an intervention program needs to extend beyond statistical significance and assess the practical value or the importance of an intervention for the targeted population and/or stakeholders. Understanding the clinical significance of programs has important implications for the implementation of a program (Part IV) and public policy. When making programmatic decisions, public policy makers generally consider effectiveness (Did the intervention result in outcomes or benefits that are important?), efficiency (program benefits vs. costs), and equity (number of people likely to benefit from the program) and cost.
We recommend that multiple measures of clinical significance be included in intervention assessment batteries, of course without adding to participant burden (Table 17.1). However, as noted throughout this chapter, there are a number of challenges associated with the measurement of clinical significance and thus these measures need to be carefully chosen. An initial consideration is operationalizing the construct of clinical significance—what constitutes meaningful change? This might include a reduction in symptoms, lessened impairment, enhanced coping skills, or QoL. It also might mean maintaining people at moderate levels of impairment or preventing further deterioration. The costs of achieving practically important outcomes also need to be considered. A program may be effective; however, the costs associated with program implementation in terms of staff resources may outweigh the benefits.
Other challenges associated with the assessment of clinical significance are the lack of normative data for some measures and identification of cutoff points that equate to “normal” functioning. Strategies also need to be identified for combining data for multiple measures and for handling the overlap that is likely to exist among measures.
Clearly, the study of clinical significance is a fruitful and important area of investigation. To the extent that we reach the goal of achieving reliable and clinically significant outcomes, we will not only make a meaningful difference in solving health and social problems and improving the lives of individuals and families, but we will also advance the field of behavioral intervention research.