Sources

What this site is built on.

Updated 5 November 2026

Every claim on this site goes back to one of these publications. We link to them so you can check our reading.

1. Goldberg, L. R. (1992). The development of markers for the Big-Five factor structure. Psychological Assessment, 4(1), 26–42.
   The fifty statements used in the check.
2. Goldberg, L. R., Johnson, J. A., Eber, H. W., et al. (2006). The International Personality Item Pool and the future of public-domain personality measures. Journal of Research in Personality, 40(1), 84–96.
   Why the IPIP statements are free to use.
3. International Personality Item Pool: ipip.ori.org
   The public-domain item pool and scoring keys.
4. Soto, C. J. (2019). How replicable are links between personality traits and consequential life outcomes? Psychological Science, 30(5), 711–727.
   What the five traits are, and are not, linked with in everyday life.
5. Roberts, B. W., Luo, J., Briley, D. A., et al. (2017). A systematic review of personality trait change through intervention. Psychological Bulletin, 143(2), 117–141.
   Traits can change, especially emotional steadiness.
6. Hudson, N. W., & Fraley, R. C. (2015). Volitional personality trait change: Can people choose to change their personality traits? Journal of Personality and Social Psychology, 109(3), 490–507.
   People who wanted to change a trait shifted a little over 16 weeks.
7. Stieger, M., Flückiger, C., Rüegger, D., et al. (2021). Changing personality traits with the help of a digital personality change intervention. PNAS, 118(8), e2017548118.
   Small daily steps over three months, supported by an app.
8. Gollwitzer, P. M., & Sheeran, P. (2006). Implementation intentions and goal achievement: A meta-analysis of effects and processes. Advances in Experimental Social Psychology, 38, 69–119.
   Why "when X, I will Y" plans help people act.

How we use them is explained in how it works.