Outline for Session 8

Critically Appraising Randomized Control Studies

· Types of Experimental Designs

· Threats to Internal Validity

· Threats to External Validity

· Statistical Significance and Effect Size

The objective of this week's class is to teach students to critically appraise an experiment, or more precisely, a randomized control trial. Because these studies represent the “gold standard” of outcome studies and represent the building blocks of systematic reviews, it is critical that we start here when learning to appraise studies we’ve found through our search. For the next three weeks, everything we do is applicable to the final assignment – after this we will talk about studies to answer assessment and descriptive PICOs, program evaluation, and talk about the course in the context of the rest of your learning. After these three classes, you should have everything you need to complete the final assignment (and maybe even turn it in early???).

Today we will review the content of Rubin's Chapter 5 as it relates to experiments as evidence for practice, look at Greenhalgh’s Chapters 5 and 6, and also look at the CONSORT guidelines as one way to think about what you are reading. We will also talk about effect size – how to calculate and how to interpret them, all using real data from the Berzin article on Family Group Decision Making. We will compare notes on how to appraise the Berzin article using both CONSORT and some of the checklists in the Appendix of Greenhalgh’s book.