The present paper addresses three issues surrounding
Rest’s Defining Issues Test, an objective
test of moral development based on Kohlberg’s six-stage
theory of moral development. Those issues are
(1) the stability of test scores over time; (2) correlation
of scores with Kohlberg’s interview measure of
moral development; and (3) the insensitivity of its
scoring procedure, which ignores responses to all
items keyed to lower stages. In two age heterogeneous
samples, total score test-retest reliabilities were
generally in the high .70’s or low .80’s, regardless
of which of several scoring schemes was used. In
another age heterogeneous sample, the correlation
with scores on Kohlberg’s test was .70; but in two
age homogeneous samples, the correlations were
about .35 and .20. These validity coefficients suggest
that (1) the common variance shared by Rest’s
and Kohlberg’s tests in age heterogeneous samples
can be attributed to the fact that scores on both
tests increase with age and (2) the two tests cannot
be considered equivalent measures of the same construct
differing only in format. Results also indicated
that an empirically weighted scoring
scheme is more sensitive to longitudinal change
than is Rest’s P score. This sensitivity to longitudinal
trends is an important property for tests
such as Rest’s which claim to be developmental and
are frequently used to assess educational change.
The empirically weighted sum had a significantly
higher test-retest reliability (p < .05) than did a
simple sum of item responses, and it had a significantly
higher correlation with Kohlberg’s measure
than did a theoretically weighted sum.
Davison, Mark L & Robbins, Stephen. (1978). The reliability and validity of objective indices of moral development. Applied Psychological Measurement, 2, 391-403. doi:10.1177/014662167800200314
Davison, Mark L.; Robbins, Stephen.
The reliability and validity of objective indices of moral development.
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