"Meta-analysis is a way of sifting through published studies against a quality standard that looks at a number of reliability criteria such as potential for bias. Then the ones that pass the standard are taken through a statistical process to find out if they are saying something consistently reliable."
Wow! Meta-analysis looks to me to have incredible potential for being able to skew results in absolutely any preconceived direction.
By simply adjusting the "reliability criteria" until you have the studies you do not like thrown out you can produce results to please anyone willing to pay for your study.
We have not seen the last of "Meta-analysis".
LOL! And I was only thinking that meta-analysis might just be compounding exponentially the inadequacies of the earlier studies! You're right though -- it's the wave of the future!