Given estimates from primary studies and the weights of the single studies calculate Cochran's Q as a measure of heterogeneity.
cochran.Q(x, weights)A named vector of length 3. First element is Q followed by the p-value and the degrees of freedom.
numeric, typically a vector of effect sizes like (log-)OR
numeric, see Details
Philipp Doebler <philipp.doebler@googlemail.com>
In fixed effects settings the weights are often inverse proportional to the variances of the primary studies. Cochran's Q is known to have low power to detect heterogeneity.