9.1.1  Do not start here!

It can be tempting to jump prematurely into a statistical analysis when undertaking a systematic review. The production of a diamond at the bottom of a plot is an exciting moment for many authors, but results of meta-analyses can be very misleading if suitable attention has not been given to formulating the review question; specifying eligibility criteria; identifying, selecting and critically appraising studies; collecting appropriate data; and deciding what would be meaningful to analyse. Review authors should consult the chapters that precede this one before a meta-analysis is undertaken.