A primary goal of scale development is to create a valid measure of an underlying
construct. We discuss theoretical principles, practical issues, and pragmatic decisions to
help developers maximize the construct validity of scales and subscales. First, it is
essential to begin with a clear conceptualization of the target construct. Moreover, the
content of the initial item pool should be overinclusive and item wording needs careful
attention. Next, the item pool should be tested, along with variables that assess closely
related constructs, on a heterogeneous sample representing the entire range of the target
population. Finally, in selecting scale items, the goal is unidimensionality rather than
internal consistency; this means that virtually all interitem correlations should be moderate
in magnitude. Factor analysis can play a crucial role in ensuring the unidimensionality and
discriminant validity of scales.