it is likely that the failure of endophenotypes in general to lead to verified molecular genetic discovery is due to poor measurement. For one thing, it is unlikely that the candidate endophenotypes listed in Table 5 are uniformly poorly measured. In addition, most are heritable, and we argue in section 5.2 that large MZ twin correlations can be viewed as a form of reliability. Endophenotype researchers should always be concerned with the psychometric properties of their measures (e.g., see W. G. Iacono & Malone, 2011). However, the results of our review suggest that a change in perspective is what is needed more than (just) improved measurement reliability and increased methodological sophistication. Despite the fact that electrophysiological endophenotypes have to date largely failed to meet the rigorous criteria we enumerated in Table 1, there are nevertheless molecular genetic endophenotype studies that stand out from the rest because they represent a step in the right direction.
