They are considered to be universal in that they are necessary conditions for success at each stage of development. The selection of the foundation factors was based on theory and a large body of research that provides evidence of the effects of each factor on student outcomes. A "potent" factor is one that has a strong correlation with an outcome or set of outcomes. For example, the quality of classroom instruction is arguably the most important driver of student outcomes during the schooling period (Anderson, 2004, Rosenshine, 2010, Kyriakides, Christoforou and Charalambous, 2013, Creemers and Kyriakides, 2006).