I came across a good website today, produced by the Rehab Institute of Chicago, et al. It’s a rehabilitation measures database, containing descriptions of hundreds of instruments used in research studies and clinical practice. Each entry has a description of the measure, how long it takes to administer, statistical data such as inter-rater reliability, and a link to the instrument itself.
For example, perhaps you (like me) can’t rattle off the components of the Berg Balance Scale, and don’t know whether the 4 point change described in a Parkinson’s disease study is clinically meaningful. The entry on this scale reports that the minimal detectable change for this scale is 5 points, meaning that any change lower than this could be due to measurement error rather than a true clinical change. There’s even a link on the home page to a glossary of the statistical terms employed.
In the context of the PICO method, this database helps us understand the “O”–the outcome. We need to know what the outcome measure was, whether it is a well-validated one for the question under study, and whether the finding in the study is clinically meaningful. It appears to be a nice little reference for this.