For over 20 years, the Defining Issues Test (DIT) has used the P index
. In view of criticisms, a search has been underway for a new index. T
he authors propose a working definition of construct validity, systema
tically reanalyze existing data sets (''classic'' studies) with new in
dexes, and make comparisons to trends obtained using the P index. The
criteria for construct validity are (a) sensitivity to educational int
erventions, (b) differentiation of age-educational groups, (c) upward
movement in longitudinal studies, (d) correlations with moral comprehe
nsion, (e) correlations with prosocial behavior, and (f) correlations
with civil libertarian attitudes. As meta-analysis demonstrates, a new
index, N2, generally outperforms the P index.