While this bias is a concern for retrospective meta-analyses, it should not be an issue for a prospective collaborative GWA investigation performed within a consortium of investigators. In this setting, there is no reason why investigators would select to include in the calculations only the most impressive results. However, a particular threat for the credibility of GWA results occurs, if several GWA investigations are performed and results are made available only for the most significant p-values in each GWA investigation. While this deficit will hopefully be remedied by quick release of genome-wide data in the future, the majority of studies have not done so yet.
