Scientific background: Big Five
About this test
This test is based on the International Personality Item Pool (IPIP), a freely available collection of personality items developed as a public alternative to commercial questionnaires like the NEO-PI-R. The 50 items used here correspond to the well-known IPIP representation of the five factors after Costa & McCrae (Goldberg, 1992) -- specifically the IPIP's 10-item scale for each factor. This is for self-reflection, not diagnostic classification. Studies on the Five-Factor Model show robust international replication of the factor structure, as well as good test-retest reliability over periods of several years.
International validation studies report satisfactory internal consistency for all five scales for a freely available research instrument (Cronbach's alpha typically between .73 and .84), along with good agreement with established commercial questionnaires like the NEO-FFI. That agreement isn't equally strong across all five dimensions, though: it's highest for Conscientiousness, Extraversion, and Emotional Stability, and noticeably lower for Agreeableness and Openness to Experience -- a known weak spot that shows up in other Big Five questionnaires too, and worth keeping in mind when interpreting those two scores specifically.
Dimensions
Extraversion
Sociability, activity level, and the tendency to experience positive emotions around others.
Agreeableness
Compassion, cooperativeness, and consideration toward other people.
Conscientiousness
Organization, reliability, goal-directedness, and self-discipline.
Emotional Stability
Composure and resilience under stress. A low score corresponds to a high level of neuroticism.
Openness to Experience
Imagination, intellectual curiosity, and interest in new ideas and experiences.
Sources & license
Goldberg, L. R. (1992). The development of markers for the Big-Five factor structure. Psychological Assessment, 4(1), 26–42.
International Personality Item Pool (IPIP) -- per ipip.ori.org's own permissions page: "the IPIP has been placed in the public domain, permission has already been automatically granted for any person to use IPIP items, scales, and inventories for any purpose, commercial or non-commercial." Item wording was verified verbatim against the IPIP's own published 50-item Big-Five Factor Markers page; the original IPIP response scale (accuracy of self-description) was adapted here to an agreement scale for consistency with the rest of the site -- IPIP explicitly permits this kind of adaptation.
https://ipip.ori.orgConstantinescu, P.-M., & Constantinescu, I. (2016). The adaptation of the Big-Five IPIP-50 questionnaire in Romania revisited. Bulletin of the Transilvania University of Braşov, Special Issue, 9(58).
Scientific publication, cited as evidence for reliability and convergent validity.
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