The hierarchy of consistency: A review and model of longitudinal findings on adult individual differences in intelligence,personality and self-opinion

When viewed in the aggregate, studies of the longitudinal consistency of intelligence, personality traits and self-opinion (self-esteem, life satisfaction etc.) show a hierarchy of consistency. Uncorrected retest coefficients over periods of 6 months to 50 yr are analyzed as the product of period-free reliability (R) and the true stability of the construct (sⁿ, where s is the coefficient of annual stability and n the number of years of the retest interval). The annual stabilities of intelligence, personality traits and self-opinions are estimated as 0.99, 0.98 and 0.94, respectively. While intelligence and personality may be regarded as relatively stable characteristics over the length of the adult lifespan, self-opinion has little stability over periods of more than 10 yr. The hierarchy of consistency should be taken into account in causal models of human development. Although self-opinion is not a longitudinally-stable characteristics, it may still be predicted over long periods of time by higher-order constructs such as personality traits and intelligence.