There is substantial evidence on the importance of personality traits in predicting socioeconomic outcomes including job performance, health, and academic achievement (Barrick and Mount 1991; Hampson et al. 2006; Hogan et al., 1996; Hogan and Holland 2003; Robbins et al. 2006; Roberts et al., 2007, Ones et al. 2007; Schmidt and Hunter 1998). Personality is also a key factor that can have important consequences for the economic decisions that individuals make and the outcomes they achieve (Cobb-Clark & Schurer, 2012). The stability of personality traits over time is essential for predicting life and economic outcomes.
Until the mid-1980s, the dominant attitude among personality theoreticians was that personality changes throughout life as the individual passes through psychological stages (e.g. Erik Erikson, in Munley, 1977). However, recent studies provide support to the stability of personality traits over time.
According to Paul Costa (1987), a well-known personality researcher, there is no evidence for personality change due to age. "It is their habits that change, their vigor and health, their responsibilities and circumstances – not their basic personality" (Costa, Vancouver, 1987).
A study by Gustavsson et al. (1997) found that personality traits, as assessed by the Karolinska Scales of Personality (KSP) remained stable after 9 years. Reviewing the data from a nationally-representative panel survey that includes measures of Big-Five personality traits of more than 7,600 Australian households, in two phases (2005 and 2009), Cobb-Clark & Schurer (2012) concluded that personality traits do appear to be stable among working-age adults. Moreover, there was little evidence that economically meaningful, intra-individual personality change can be linked to the adverse employment, health, or family events that individuals experience.