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. Author manuscript; available in PMC: 2026 Feb 1.
Published in final edited form as: J Pers Soc Psychol. 2025 Jan 13;128(2):392–409. doi: 10.1037/pspp0000531

Table 2.

Study and Sample Characteristics

Sample Analytic N (Participants) Analytic N (Measurement Occasions) Country of Data Collection Year of Baseline Assessment % Female Mean (SD) Baseline Age
MIDUS 4,092–4,093 10,766 – 10,805 United States 1994–1995 55 47.2 (12.4)
NAS 1,606 8,606–8,630 United States 1975 0 51.0 (8.8)
WLS 9,394–9,397 24,856–25,487 United States 1992/1993 54 53.0 (4.2)
SATSA 1,647–1,703 7,721–8,540 Sweden 1984 59 58.6 (13.8)
SLS 1,083 3,565 United States 2001 56 62.2 (14.4)
HRS 11,028–11,031 29,192–29,387 United States 2006/2008 60 67.3 (9.7)
LASA 1,623 4,477 The Netherlands 1992 52 68.1 (8.2)
LBC 787 2,663–2,673 United Kingdom 2004–07 49 69.5 (0.8)
EAS 504–506 1,836–1,883 United States 2005–2016 61 79.0 (5.0)
BASE 210 554–677 Germany 1990–93 50 79.8 (6.9)
OCTO 309 917–923 Sweden 1991 63 82.6 (2.2)

Note. Samples are shown in order from the youngest to oldest mean age at study baseline. Ranges for analytic N indicate ranges across the Big Five traits. The analytic N includes participants with personality trait data at analytic baseline and at least one additional measurement occasion and is thus smaller than the total sample N. MIDUS = Midlife in the United States Study. NAS = Normative Aging Study. WLS = Wisconsin Longitudinal Study. SATSA = Swedish Adoption/Twin Study of Aging. SLS = Seattle Longitudinal Study. HRS = Health and Retirement Study. LASA = Longitudinal Aging Study Amsterdam. LBC = Lothian Birth Cohort. EAS = Einstein Aging Study. BASE = Berlin Aging Study. OCTO = Origin of Variances in the Oldest Old: Octogenarian Twins Study.