IMED2003 Study Guide - Final Guide: Causal Closure, Dependent And Independent Variables, Type I And Type Ii Errors
11 Jun 2019
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Document Summary
Failing to discriminate between intervention effects at the group level and at the single-subject level is a common mistake. A statistically significant effect at the group level does not mean you should assume every person has benefited. In order to determine the degree to which a particular person has been changed by the outcome: Measure during the course of the intervention, researchers need to compute a reliable change index (rc) for that person: The degree to which the person changes on the outcome variable divided by: The standard error of difference between the pretest and post-test scores. When the rc is greater than 1. 96 : It is likely that the post-test score is reflecting a real change rather than measurement error. Failure to sample across a sufficiently broad range of scores is a common problem. If you restrict the range the sample correlation becomes attenuated such that it underestimates true population value.
