Another possible limitation in the current study is the assessment of the personality trait of neuroticism. Even though the measure of neuroticism utilized here is based on several well-known trait scales (e.g., Goldberg, 1992; John, 1990; Trapnell & Wiggins, 1990), it consisted of only four single-word adjectives, and may not only underrepresent the construct of neuroticism but also be prone to mood-state distortion. We are confident, however, that there are several reasons why this is unlikely to be the case. First, it has been suggested that different measurement formats of the FFM (e.g., adjectives vs. full statements) are basically equivalent (John, 1990). Second, the particular FFM measure has been used successfully in other MIDUS research (e.g., Plant, Markus, & Lachman, 2002; Staudinger, Fleeson, & Baltes, 1999). Third, neuroticism as a structurally and etiologically coherent structure was clearly revealed in phenotypic and genetic factor analyses using the same base twin sample as used in the current study (Johnson & Krueger, 2004).
