If averaging appraoches make so much of a difference, what appraoch should you use- #1 or #2
If you are conducting
We do this because
It’s sort of like the way we organize sporting competitions. We don’t choose the best team in the world as the one with the best overall record because all the teams are not playing against the same level of competition.
Instead, we have teams compete within their league (the same environment) and then we have competitions across environments by having the champions of each league compete in a final tournament.
But, what if we know that one league is more competitive than another league? Or we believe that one study is more reliable than another?
Meta-analysis can account for those differences using what we call “weighting.”