Statistical Harmonization Methods in Individual Participants Data Meta-Analysis are Highly Needed

Abstract

Meta-analysis has a long history within the medical sciences and epidemiology [1,2,3]. The main goal of a meta-analysis is to improve the precision of a specific effect size of a treatment or an exposure on a clinical or disease outcome by pooling or combining multiple studies. It is frequently conducted within a systematic review of the scientific literature to guarantee that studies with appropriate information are not ignored or overlooked and to make sure that the pooled estimate represents an unbiased and precise estimate of the true effect size. Moreover, the pooled effect estimate is evaluated in the context of study heterogeneity. In case substantial heterogeneity in the effect sizes across studies is present, the pooled estimate is considered less reliable or even questionable. Thus not only the pooled estimate must be unbiased, also the estimate of the measure of heterogeneity should be correct. Within the area of medical statistics, meta-analysis has evolved into an important and rich research field [4,5].