Researchers from the University Medical Center Groningen and the Amsterdam University Medical Center calculated scores for several facets and five factor inventory (FFI) scales of the Personality (NEO) from participants aged 18-65 at 1A questionnaire 2. Lifelines combined these scores to create one personality sum score. (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 the calculation of the actual sum scores.

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 should be reversed in order 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 neoinputed_…

Besides the different sum scores, the number of valid items is provided. Enabling everyone to

total facet = 8, total FFI = 12 o SUM1 for Extraversion as one variable is missing (11 vs 12 items)!! Note that even in the old versions of the questionnaire, i.e. before adding the missing FFI items, the questionnaire did already contain some FFI items: 5 out of 12 FFI neuroticism items, 3 out of 12 FFI conscientiousness items, and 1 out of 12 FFI extraversion items. Therefore, FFI SUM2 and FFI SUM3 are calculated even for subjects who were administered an old version of the questionnaire. Thus, any researcher using these scores must always check the number of missing items per scale and set his/her own threshold for missingness.

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