Table 1.

Meta-analysis pooled effects modelsa.

	Fixed effects	Random effects	Quality effects
Weights
Estimator
Estimator variance

^a is the estimated effect size of jth study, v_j is the sampling error variance of jth study, τ² is the DerSimonian and Laird estimator of the between-study variance, Q_j is the jth study rank (scaled between 0 and 1), and is a bias correction (where N is the number of studies).