Bayesian analyses allow for the incorporation of external information or opinion on the nature of bias (see Chapter 16, Section 16.8) (Turner 2008). Prior distributions for specific biases in intervention effect estimates might be based on empirical evidence of bias, on elicited prior opinion of experts, or on reasoned argument. Bayesian methods for adjusting meta-analyses for biases are a subject of current research; they are not currently sufficiently well developed for widespread adoption.