biostudies-literatureUnknown10(11)Bask MTo foster a deeper understanding of the mechanisms behind inequality in society, it is crucial to work with well-defined concepts associated with such mechanisms. The aim of this paper is to define cumulative (dis)advantage and the Matthew effect. We argue that cumulative (dis)advantage is an intra-individual micro-level phenomenon, that the Matthew effect is an inter-individual macro-level phenomenon and that an appropriate measure of the Matthew effect focuses on the mechanism or dynamic process that generates inequality. The Matthew mechanism is, therefore, a better name for the phenomenon, where we provide a novel measure of the mechanism, including a proof-of-principle analysis using disposable personal income data. Finally, because socio-economic theory should be able to explain cumuPloS onee0142447https://www.ebi.ac.uk/biostudies/studies/S-EPMC4659671biostudies-literatureCumulative (Dis)Advantage and the Matthew Effect in Life-Course Analysis.PMC4659671Bask MfalseCumulative (Dis)Advantage and the Matthew Effect in Life-Course Analysis.To foster a deeper understanding of the mechanisms behind inequality in society, it is crucial to work with well-defined concepts associated with such mechanisms. The aim of this paper is to define cumulative (dis)advantage and the Matthew effect. We argue that cumulative (dis)advantage is an intra-individual micro-level phenomenon, that the Matthew effect is an inter-individual macro-level phenomenon and that an appropriate measure of the Matthew effect focuses on the mechanism or dynamic process that generates inequality. The Matthew mechanism is, therefore, a better name for the phenomenon, where we provide a novel measure of the mechanism, including a proof-of-principle analysis using disposable personal income data. Finally, because socio-economic theory should be able to explain cumu2015-01-01T00:00:00Z20152025-04-04T03:42:43.142Z2019-03-26T23:28:16ZS-EPMC46596712660638610.1371/journal.pone.0142447