It has been argued that the revised Minnesota Multiphasic Personality
Inventory (MMPI-2) fails to measure the Big Five dimension of conscien
tiousness (C), an assertion supported by the research finding that non
e of the factors underlying the MMPI correlate substantially with the
C factor of the NEO Personality Inventory (NEO-PI)-a popular operation
alization of the Big Five model. In this study we reconsidered the rel
ationship between the MMPI-2 item pool and the C factor of the NEO-PI-
R (Form S). Collections of MMPI-2 C markers did not correlate much hig
her than .5 with the NEO-PI-R factor scale in cross-validation hold-ou
t samples. Most pervasive, however, was the finding that MMPI-2 item m
arkers of C were also strongly (in many cases, more highly) related to
the NEO-PI-R factor of neuroticism (N). Efforts to purify collections
of MMPI-2 C markers, first by careful item selection and then by supp
ression of N variance, were met with limited success. Intercorrelation
s among NEO-PI-R scales suggest that the difficulty in finding markers
that discriminate between N and C extends beyond any shortcomings of
the MMPI-2 item pool.