Session 7: Criteria for Inferring Effectiveness

·         Internal Validity

·         Measurement Issues

·         Statistical Chance

·         External Validity

·         Ethics

·         Relevance to Clinical Context and Client

The objective for class this week is to provide students with a beginning understanding of the basic criteria for appraising the scientific validity of studies concerning the effectiveness of social work interventions and policies.

We will begin with what I hope is a review for most of you:  The philosophy of science concerning the understanding of causality, i.e., how we know that an independent variable ("the cause") is responsible for changes in a dependent variable ("the effect").  From there, we will go on to talk about 4 different perspectives from which we can judge how well a particular study addresses whether a particular intervention causes a particular change in the person/people for whom it is intended.  These four criteria include internal validity, which is the extent to which alternative explanations for change are ruled out; measurement issues, which concern whether the way we measure outcomes may contain systematic error; statistical chance, which concerns how much random error is present; and external validity, which concerns the extent to which the findings from a particular study can be extended, or generalized, beyond the study.

We also need to preview some issues related to research. 

Finally, we will begin to talk about ways in which to evaluate the applicability to our clients and clinical context.

This is some tough stuff, but I think that the Rubin text does an excellent job of addressing these issues!

See you in class!

Jo