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Methodology note

Methodology of the Big Five personality test questionnaire

  • Self-observation
  • 30 items
  • 5 axes
  • 3 references

This page describes where the items come from, how the score is computed and the limits of this questionnaire. It is public and asks for no sign-up.

1Where the items come from

The items are written for Brain Quiz from the published literature in the field.

The 30 items in this questionnaire were written for Brain Quiz from the literature on the five-factor model. No published inventory is reproduced. The International Personality Item Pool, whose items are placed in the public domain by the Oregon Research Institute, was explored and its public-domain notice checked on ipip.ori.org on 8 August 2026. It was not used as the source of the items: the site itself flags that the accuracy of its French and Spanish translations has not been verified by the project, which rules out any claim of faithful reproduction in three languages. No item from the NEO-PI-R or the BFI-2, both under copyright, is used.

Sources. 30 items in total.1,2,3

2How the score is computed

Each answer is worth 0 to 4 points, multiplied by the item weight. The total is rescaled to 100, and each of the five factors is computed separately, as a percentage of the maximum reachable on its own questions. The overall score of this questionnaire mainly reflects the emotional reactivity axis: its six items carry a weight of 5, against 1 for the other twenty-four. The five factors are read axis by axis, and none of the five is better than another: a high or low score on a factor describes a tendency, not a quality. The weights and the band thresholds were set by the editorial team: they come from no population calibration.

2.1The reading axes

Each item feeds a single axis. Each axis is computed as a percentage of the maximum reachable on its own items.

Table 1. The 5 reading axes and the number of items feeding each one.
Reading axisItems
Openness to experience6
Conscientiousness6
Extraversion6
Agreeableness6
Emotional reactivity6

2.2The reading bands

The score brought back to 100 falls into one of these bands. The bounds are set by the editorial team, and shown here.

Table 2. The reading bands of the score out of 100, and the guidance attached to each one.
BandRange out of 100Guidance
Low emotional reactivity0 to 29nonea
Moderate emotional reactivity30 to 54nonea
High emotional reactivity55 to 79conversation suggestedb
Very high emotional reactivity80 to 100reinforced guidancec
  1. No guidance message comes with this band.
  2. The result mentions that a conversation with a professional can help.
  3. The result shows a guidance message towards a health professional.

3Limits of the result

This questionnaire describes average behavioural tendencies, not abilities or skills. It predicts neither professional success nor compatibility with another person. No profile is better than another. A personality questionnaire must not serve as the basis for a hiring decision, and it can neither establish nor rule out a condition.

4References

Each entry carries its authors, year, title, journal and identifier.

  1. Goldberg, L. R. (1992). The development of markers for the Big-Five factor structure. Psychological Assessment, 4(1), 26-42. doi:10.1037/1040-3590.4.1.26 opens in a new tab ↑
  2. Goldberg, L. R., Johnson, J. A., Eber, H. W., Hogan, R., Ashton, M. C., Cloninger, C. R., & Gough, H. G. (2006). The international personality item pool and the future of public-domain personality measures. Journal of Research in Personality, 40(1), 84-96. doi:10.1016/j.jrp.2005.08.007 opens in a new tab ↑
  3. Soto, C. J., & John, O. P. (2017). The next Big Five Inventory (BFI-2): Developing and assessing a hierarchical model with 15 facets to enhance bandwidth, fidelity, and predictive power. Journal of Personality and Social Psychology, 113(1), 117-143. doi:10.1037/pspp0000096 opens in a new tab ↑
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