Recent literature has suggested many ways of measuring equality of opportunity. We analyze in a systematic manner the various approaches put forth in the literature to show whether and to what extent different choices matter empirically. We use EU-SILC data for most European countries for 2005 and 2011. The choice between ex-ante and ex-post approaches is crucial and has a substantial influence on inequality of opportunity country orderings. Growth regressions also illustrate the relevance of conceptual choices. We only find significant negative effects for some direct parametric ex-ante measures.