Researchers from the University Medical Center Groningen and the Amsterdam University Medical Center calculated scores for several facets and five factor inventory (FFI) domains of the Personality (NEO) from participants aged 18-65 at 1A questionnaire 2. Lifelines combined these calculations. (sections: mental health (Personality (NEO)) and secondary & linked variables)

The personality sum scores (NEO) can be requested in the Lifelines catalogue or by mail (data@lifelines.nl).

In Lifelines, selected items of the NEO-PI-R were administered. Initially, 64 items (8 items belonging to 8 personality facets) were administered. At some point during the data collection process (approximately 80% of the sample had already taken part at that point), the following specific items were added:

• All items of the anxiety and depression facets, such that now we have a detailed assessment of the entire neuroticism domain, including all individual facet scores, a total score, and the FFI estimation of the total score.
• All missing FFI items for the conscientiousness domain, such that now we have an FFI estimation of the conscientiousness domain total score
• All missing FFI items for the extraversion domain, such that now we have an FFI estimation of the extraversion domain total score. Unfortunately, by mistake, one FFI item of the Extraversion domain was not included in the updated questionnaire.
  

The calculation of the personality sum scores consisted of two steps. The first being data preparation and the second is the calculation of the actual sum scores of the different facets and the domains.

First, the variables for each facet and FFI domain were named according to their facet/domain (e.g. C1-C8 for the competence facet). Additionally, some items of the questionnaire were reversed to calculate an appropriate sum score. A detailed overview of the variables per facet/domain and the items that are reversed can be found in the syntax on the Lifelines workspace. Finally, variables have been created indicating the number of valid answers per facet and domain.

Because different researchers might find a different number of missing values acceptable, 3 different sum scores have been calculated.

1. A sum score for all participants with complete data (no missing items) → variable name neocomplete_….
2. A sum score for the available items for all participants → variable name neovalid_…
3. A sum score for all participants with at least one valid item, with missing items imputed to the mean of all non-missing items → variable name neoimputed_…

Besides the different sum scores, the number of valid items is provided. Enabling everyone to decide how many valid answers is enough to include a sum score.

• The total number of items for a facet is 8, for a domain this is 12. As a result, the sum score for facets ranges from 0-40 and for the domains from 0-60.
• The FFI item extraversion has one missing question. As a result, no sum score item number 1 has been calculated (as there is always at least one missing question).
• Even though all FFI items have been included in only part of the questionnaires, the FFI sum scores have been calculated for all domains. This has been decided because before adding the missing items, the questionnaire did already contain some FFI items.

• Schweren, L. J., Larsson, H., Vinke, P. C., Li, L., Kvalvik, L. G., Arias-Vasquez, A., ... & Hartman, C. A. (2021). Diet quality, stress and common mental health problems: A cohort study of 121,008 adults. Clinical Nutrition, 40(3), 901-906. https://doi.org/10.1016/j.clnu.2020.06.016