Assessing Publication Bias in Meta-Analysis

BACKGROUND: Although publication bias is a concern when using meta-analysis, techniques for assessing for its potential appear to be underused in nursing. OBJECTIVES: To demonstrate several methods, both graphical and statistical, of assessing for publication bias. METHODS: Four methods are described and demonstrated, ranging from the familiar fail-safe N to the trim-and-fill method, using the same contrived data set. RESULTS: Methods vary in their conclusion about the presence of potential publication bias in the example presented. Some limitations of the methods are noted to assist meta-analysts in determining which to consider using. CONCLUSION: Given that publication bias can affect the validity of meta-analytic studies, researchers are encouraged to use more than one method to assess for bias so that clinicians and decision-makers can have the best possible information available.