Publication bias in meta-analysis: Prevention, assessment and adjustments

Each study that is published about the effect of an independent variable on a dependent one, or the strength of the relationship between two variables, constitutes only a single piece in a constantly growing body of evidence.For example, over one hundred studies have been carried out to determine the relationship between employment interview performance and job performance (McDaniel, Whetzel, Schmidt, & Maurer, 1994).Each study yields a measure of the strength and direction of the association, typically in the form of a correlation coefficient.In some studies, the correlation coefficient is statistically significant, while others do not find a statistically significant association.To make sense of the often-conflicting results found in the literature, one can conduct a meta-analysis (e.g.