Archives of Psychiatry and Psychotherapy, 2015; 1 : 21–32 DOI: 10.12740/APP/36086 Efficient and valid assessment of personality traits: population norms of a brief version of the NEO Five-Factor Inventory (NEO-FFI) Annett Körner, Zofia Czajkowska, Cornelia Albani, Martin Drapeau, Michael Geyer and Elmar Braehler Summary Aims: The NEO Five-Factor Inventory (NEO-FFI), a well-established 60-item questionnaire based on the Five-Factor Model (FFM) of personality, provides a valuable framework for the interdisciplinary approach to personality research and clinical practice. In response to the need for briefer personality measures, a 30-item version of the NEO-FFI (NEO-FFI-30) was developed and its factor structure replicated. Method: The study examines the psychometric quality of NEO-FFI-30 and provides population-based norms (n=1908 adults). Reliability coefficients, kurtosis, skewness, correlations and effect sizes illustrate the psychometric properties of the measure. Results: The relationships between neuroticism, extraversion, openness, agreeableness, conscientiousness and sociodemographic characteristics confirm previous research findings and speak to the validity of the brief version. Namely, women report higher neuroticism and agreeableness. Younger individuals indicate more extraversion but less agreeableness and conscientiousness. Finally, openness to experience was related to higher education. Percentile ranks are provided for the total sample and for subgroups by age and gender. Conclusions: The 30-item-version of the NEO-FFI constitutes an assessment tool comparable with the full-length instrument with regard to its psychometric properties. As such, the NEO-FFI-30 is a promising alternative to longer questionnaires, as well as to single-item measures of personality used in research and clinical practice. Big Five / personality assessment / psychometric properties / population norm Personality characteristics have been shown to be robust correlates and predictors of behavioural problems, coping strategies and psychiatric disorders [1]. Personality functioning predicts the frequency of the exposure to various kinds Annett Korner1 Zofia Czajkowska1 Cornelia Albani2 Martin Drapeau1 Michael Geyer3 Elmar Braehler2,4: 1McGill University, Counselling Psychology Program, Canada; 2Medical Center of the University of Leipzig, Department of Medical Psychology and Medical Sociology, Germany: 3Academy of Psychotherapy, Erfurt, Germany; 4Department of Psychosomatic Medicine and Psychotherapy, University Medical Center Mainz, Mainz, Rhineland-Palatinate, Germany. Corespondence email: annett.korner@mcgill.ca of stressors as it affects the appraisal of events as well as the perception of one’s coping resources [2]. Research as well as clinical practice benefits from taking personality variables into account when designing and delivering psychotherapeutic interventions and psychiatric treatment regimes for mental disorders [1]. This requires sound personality models as well as valid and feasible assessment instruments. The Five-Factor Model (FFM) is a well-established paradigm for the conceptualisation of human personality, described in terms of Neuroticism, Extraversion, Openness to Experience, Agreeableness and Conscientiousness [3]. The model provides a valuable framework for the 22 Annet Körner et al. multidisciplinary approach to personality examined in relation to mental health, subclinical syndromes and personality disorders [4-7]. Research has demonstrated the replicability of the five core personality traits across cultures and languages [8-11]. The NEO Personality Inventories (NEO-PI) are among the most widely used instruments to assess the Big Five personality traits [12]. The 240-item questionnaires: NEOPI and its successors NEO-PI-Revised (NEOPI-R) and NEO-PI-3, capture 6 different facets for each of the 5 personality domains [12]. The short form of the NEO-PI, the NEO Five-Factor Inventory (NEO-FFI), was designed to capture the 5 main factors in a more economical way but does not provide facet-specific information. To maximise convergent and discriminant validity of the NEO-FFI, its 60 items were selected from the NEO-PI based on examinations of factor structure and internal consistency. The subsequent version, the NEO-FFI-R, showed “modest improvements in reliability and factor structure” [13] when compared with the NEO-FFI. However, these differences were found to be “trivial in magnitude” [13]. The authors concluded that the NEO-FFI-R and the NEO-FFI were equally valid. To further improve psychometrics and readability, McCrae & Costa developed the NEO-PI-3 and its short version, the NEO-FFI-3, with the latter being identical to the NEO-FFI-R except for the addition of one new item, “I have no sympathy for beggars” [14]. Internationally, the original 60-item NEO-FFI is the most widely used short version [15]. It is commonly used by German-speaking researchers and practitioners [16]. To date, no German translation of the NEO-FFI-R or the NEO-FFI-3 exists. Ultra-brief instruments that contain only one or two items per personality construct are available for contexts with severely limited assessment time. Although some of these extremely short measures show respectable psychometric properties, they are more susceptible to acquiescence, memory effects, socially desired responding and other assessment problems [17]. The substantially reduced reliability, content validity and criterion validity of such very brief measures demonstrate that complex constructs cannot be sufficiently captured by only one or two items [17]. Using only 30 items of the original 60-item version of the NEO-FFI (with 6 items per domain) offers a middle ground in this dilem- ma [18, 19]. The 30-item version of the NEO-FFI is currently applied in diverse research contexts [2025] as well as in clinical settings [26]. The German manual of the NEO-FFI [16] provides age- and gender-specific population norms for the original 60-item version of the measure. These normative data are based on the non-clinical participant pool of more than 50 individual studies with 12[th]552 participants who completed the NEO-PI-R in Germany, Austria and Switzerland. The authors selected a secondary quota sample of 871 males and females, which matches the population of Germany in 2001 regarding gender, age and education. To date, no normative data representative of the general population of any country have been published for the 30-item version of the NEO-FFI. The aim of the present work is to examine the psychometric properties of the NEO-FFI-30 instrument, to provide German population norms, and to introduce the NEO-FFI-30 to the larger professional community, i.e. non-German speaking researchers and clinicians. MATERIAlS AND METHOD Sample A sample representative of the German population was drawn for a multi-topic survey of the University of Leipzig, Germany, in November 1999, which included the 60 items of the NEO-FFI. The study was approved according to the ethical guidelines of the Committee of the Institutes of Market and Social Research, Germany [27], and conducted in compliance with the ethical principles of the Helsinki Declaration [28]. Participants were selected following the random-route method with 182 sample areas replicating federal election districts across Germany to systematically represent the different regions of the country [29]. In 31% of the randomly selected cases the targeted person or the household representative declined participation, resulting in a participation rate of 69%. This study includes 1908 German participants of 18 years of age or older (Table 1 – next page). Comparisons with census data showed that the sample closely matched the total population of the former Eastern and Western Germany in terms of age, education and employment status [30]. However, 55% of the sur- Archives of Psychiatry and Psychotherapy, 2015; 1 : 21–32 Eicient and valid assessment of personality traits 23 Table 1. Sociodemographic characteristics of the study sample Variable Age in years Sex Marital status Education Employment status Net household income Mean (SD) 47.7 (16.9) Range 18-96 Age groups 18 to 33 34 to 49 50 to 65 > 65 Male Female Married Single Divorced Widowed Less than 8 years of schooling* Basic secondary school (8-9 years) Secondary school (10-11 years) General qualification for university entrance Technical college (3 years) College (4 years) or university degree Still in secondary school Full-time employment >35 hours/week Part-time employment 15-35 hours/week Part-time employment < 15 hours/week Military/civilian service, maternity leave Unemployed/ 0 hours short-term employed Retired Homemaker In training < 750 €/month ≥ 750 – 1250 €/month ≥ 1250 – 2000 €/month > 2000 €/month Absolute frequency (Relative frequency) 472 580 527 329 853 1055 1045 452 165 243 57 758 680 141 100 161 1 787 118 33 25 182 554 123 78 135 480 704 514 (24.7%) (30.4%) (27.6%) (17.2%) (44.7%) (55.3%) (54.9%) (23.7%) (8.7%) (12.8%) (3.0%) (39.9%) (35.8%) (7.4%) (5.3%) (8.5%) (0.1%) (41.4%) (6.2%) (1.7%) (1.3%) (9.6%) (29.2%) (6.5%) (4.1%) (7.4%) (26.2%) (38.4%) (28.0%) Note. 1833 ≤ N ≥ 1908 (Household income not reported by 75 participants. Missing data for the other variables range between 0 and 10); * Starting with grade 1 vey respondents were women while only 51% of the total population are female. Furthermore, 55% of the participants were married compared with 47% in the general population. Measures The NEO-FFI captures the Big Five personality traits with item responses ranging from 0 (“strong disagreement”) to 4 (“strong agreement”) [31, 32]. The use of only 30 of the orig- inal 60 items of the NEO-FFI was proposed in response to the examination of the factor structure of the original instrument in the above-mentioned German population sample [33]. Whereas previous studies had used various research samples (university students, individuals in training to become military officers, etc.), this was the first work reporting on the factor structure in the general population. Numerous items did not load highest on their respective factor. The differentiation between Agreeableness and Consci- Archives of Psychiatry and Psychotherapy, 2015; 1 : 21–32 Annet Körner et al. 24 entiousness seemed particularly compromised as 6 items (3 items from each scale) showed highest loading on the “wrong” factor [33]. The proposed abbreviated version, the NEO-FFI-30, includes 6 items per scale, all of which showed the highest corrected item-scale correlation for their respective original NEO-FFI scale based on the study sample described above [18]. The fivefactor structure across these 30 items was replicated in a second population sample with 2508 adults [18]. compared with the range of 0.63 to 0.82 for the original, twice-as-long scales of the NEO-FFI. Part-whole correlations between the abbreviated and the original scales ranged between 0.88 for Openness to Experience and 0.93 for Neuroticism. The mean scores for Neuroticism, Extraversion and Openness differed only minimally when computed using the abbreviated versus the original scales (Table 2). Cohen’s effect size indicated moderate differences between the 6- and the 12-item versions of the Agreeableness and Conscientiousness subscales. All scale means were highest for Conscientiousness and lowest for Neuroticism. Table 3 shows scale means and standard deviations of the NEO-FFI-30 by age, gender and education. Younger age groups reported higher Extraversion and lower Agreeableness and Conscientiousness. Women scored higher on Neu- RESulTS Item characteristics Each item of the Neuroticism subscale correlated with the entire subscale (after excluding Table 2. Comparison of original and abbreviated version of the NEO-FFI scales Scales Neuroticism Extraversion Openness to experience Agreeableness Conscientiousness M SD Cronbach’s  rtt r ES Long version 1.62 0.62 .82 .82 .93 0.14 Short version 1.52 0.77 .81 .83 Long version 2.20 0.50 .73 .73 .89 -.14 .88 0 .91 -.44 .91 -.42 Short version 2.28 0.62 .72 .73 Long version 2.04 0.47 .63 .67 Short version 2.04 0.64 .67 .59 Long version 2.54 0.47 .72 .75 Short version 2.79 0.65 .75 .72 Long version 2.71 0.55 .82 .82 Short version 2.96 0.62 .78 .78 Note. 1,893 ≤ N ≥ 1,908; rtt = split-half reliability coefficient (Spearman-Brown); r = part-whole correlation between long and short version (Pearson); ES = effect size (Cohen) the respective item) between 0.53 and 0.62. The corrected item-scale correlation ranged between 0.40 and 0.55 for the items of the Extraversion subscale, between 0.35 and 0.46 for Openness to Experience, between 0.35 and 0.60 for Agreeableness, and between 0.51 and 0.57 for Conscientiousness. Each item correlated higher with its own subscale than with any other subscale. Psychometric characteristics of the NEO-FFI-30 Cronbach’s alpha ranged between 0.67 and 0.81 for the NEO-FFI-30 scales, which can be roticism and Agreeableness than men. The dichotomous variable of education was computed by dividing the sample into the group of individuals who completed a maximum of 11 years of general education (starting at grade 1), which generally is followed by a vocational training, versus the group of individuals who completed the 12 or 13 years of general schooling necessary to qualify for university entrance. The more educated group reported more Openness to Experience. A multivariate analysis of covariance (1/1763 ≤ d.f.≥1/172) confirmed that after controlling for the effects of the other independent variables the covariate age explained Archives of Psychiatry and Psychotherapy, 2015; 1 : 21–32 Eicient and valid assessment of personality traits 25 Table 3. NEO-FFI-30 scale scores by age, sex and education Scale Age Sex Education 18-33 34-49 50-65 > 65 Male Female ≤ 11 years > 11 years N 471 577 524 323 850 1045 1484 400 M 1.52 1.54 1.51 1.49 1.38 1.62 1.53 1.48 SD .76 .79 .77 .73 .77 .75 .78 .73 N 471 578 524 323 850 1046 1485 400 M 2.46 2.35 2.21 2.01 2.31 2.25 2.26 2.34 SD .60 .64 .57 .60 .63 .62 .63 .59 Neuroticism Extraversion Openness to N 470 578 524 322 849 1045 1484 400 M 2.08 2.06 2.03 1.97 2.04 2.05 1.95 2.39 SD .68 .68 .59 .56 .67 .60 .60 .65 N 470 578 524 323 849 1046 1485 400 M 2.65 2.75 2.87 2.92 2.71 2.85 2.80 2.74 SD .65 .65 .64 .61 .66 .64 .66 .62 N 470 579 524 324 849 1048 1486 401 M 2.80 2.94 3.08 3.02 2.94 2.97 2.97 2.95 SD .61 .64 .60 .61 .63 .62 .63 .62 Agreeableness Conscientiousness Note: N = 1908; M = mean total sum over all items of the subscale divided by number of items between 2% and 6% of the variance (i.e. partial ฀2 in the subscales of Extraversion, Agreeableness and Conscientiousness (F=107.13, P≤0.001; F=27.43, P≤0.001; and F=38.75, P≤0.001 respectively). Gender explained 0.3% to 2% of the variance of Neuroticism, Extraversion and Agreeableness (F=35.14, P≤ 0.001; F=5.12, P≤ 0.05; and F=10.15, P≤0.001 respectively), whereas education explained 8% of the variance in the Openness to Experience subscale (F=158.77, P≤0.001). There were no significant interaction effects except for the gender and education variables. However, this interaction effect explained only 0.3% of the variance of the subscales Openness to Experience and Conscientiousness and as such is considered negligible (F=4.96, P≤ 0.05 and F=4.78, P≤0.05 respectively). Population-based norms for the NEO-FFI-30 Percentile ranks for the whole sample and for the subgroups by age and gender are provided in Tables 4–8 of the Appendix. This allows for comparing personality characteristics of individuals and of groups, such as research samples, to the levels of these traits in the general population by either using the reference values for the whole study sample or for a respective subsample. Means and standard deviations are added to each table in order to permit the transformation into alternative standardized scores. DISCuSSION The high corrected item-scale correlations for all items of the abbreviated NEO-FFI instrument Archives of Psychiatry and Psychotherapy, 2015; 1 : 21–32 26 Annet Körner et al. were found to be superior to the item characteristics of the original 60-item measure for which this discrimination coefficient was less than 0.40 for 27 items and less than 0.30 for 13 items [30]. Cronbach’s alpha did not differ significantly between the original 12-item and the proposed 6-item versions of the five scales and was satisfactory for Neuroticism, Extraversion, Agreeableness and Conscientiousness. The low internal consistency for Openness to Experience seems only acceptable for group comparisons and other research purposes, but has to be interpreted in relation to the small number of items of the subscales of the NEO-FFI-30. Moreover, Cronbach’s alpha of Openness to Experience seems to reflect a general problem with the operationalization of this construct, which has been reported across languages as these items seem to focus on interests in philosophy, art and theoretical discussions rather than capturing a broader concept of openness to experience – an issue also reported for other FFM questionnaires [34]. However, it is remarkable that the shortened Openness subscale achieves an even higher Cronbach’s alpha than the original version with twice as many items (0.67 and 0.63 respectively). Despite containing only six items, the shortened scales correlate highly (between 0.88 and 0.93) with the original scales indicating that the elimination of items did not result in a significant loss of information. Cohen’s effect size indicates moderate differences between the short and the original scales for Agreeableness and Conscientiousness, which further speaks for the content validity of the short scales as these two NEO-FFI scales had been particularly problematic (only 5 of the 12 original items had their highest loading on the Agreeableness factor, 3 of the 12 original Conscientiousness items possessed the highest factor loading for Agreeableness and 1 item loaded highest on Neuroticism) [33]. The relationships of the NEO-FFI-30 scales with demographic variables such as age, gender and education confirm previous research findings and clinical experience [35-37]. Gender explained less score variance in our sample than age, yet it is a very robust finding across cultures that women report higher Neuroticism and Agreeableness than men [38, 39]. Consequently, standardised scores are reported with the total sample as reference for men as well as wom- en by age group. Overall, providing standardised scores based on a representative population sample should further facilitate the utilisation of this reliable and valid measure as an alternative to the original 60-item NEO-FFI as well as to the ultra-short measures of personality. Using the NEO-FFI-30 circumvents the common psychometric problems of measures with one or two items per personality trait while the abbreviated instrument still responds to the need for time efficiency by employing only 6 items per personality factor. This facilitates research in contexts where numerous variables have to be assessed or where personality factors are not the main focus of the study [40]. Hence, NEO-FFI-30 enables research that would not even be attempted with longer, multi-item measures. At the same time, the abbreviated 6-item scales may prevent an issue reported for single-item measures of personality characteristics - that is “to substantially underestimate the role that personality traits play in influencing important behaviours and thereby overestimate the role played by new constructs” [17, p. 874]. With 5-10 minutes of administration time, in clinical practice the questionnaires can serve as an efficient screening tool to help adjust communication strategies and intervention plans to risk-related or protective personality characteristics of the individual patient. Yet, the NEO-FFI-30 was developed based on a German population sample drawn almost 15 years ago. Based on cohort studies, one could argue that the age of the data is the lesser evil because for the population-based standardisation of personality scores there is no such thing as the Flynn effect for IQ scores. Thus, research as well as clinical practice may still benefit from the opportunity to compare NEO-FFI-30 scores of individual clients or research samples to the population norms provided here. More caution is required when consulting the German population norms as a reference for scores of examinees that are not represented in the current standardization sample of the NEO-FFI-30. Nonetheless, the present study details of the Big Five scores in the general population of Germany may be valuable for transcultural and across-language comparisons and potentially ignite and inform the examination of the NEO-FFI-30 by non-German speaking research teams. Archives of Psychiatry and Psychotherapy, 2015; 1 : 21–32 Eicient and valid assessment of personality traits 27 CONCluSIONS 3. Carducci BJ. The Psychology of Personality: Viewpoints, Research, and Applications, 2nd ed. Wiley-Blackwell; 2009. The use of only 30 items of the NEO-FFI constitutes an assessment approach comparable with the full-length instrument regarding reliability and validity. As such it provides a viable alternative to longer, multi-item instruments as well as to ultra-brief measures of personality. It allows for an efficient assessment of the Big Five personality factors without significant loss of information or psychometric quality when compared with the original 60-item measure. Future research should examine the psychometric properties of the 30-item version of the NEO-FFI in other languages and cultures. 4. Kardum I, Hudek-Knezevic J. Relationships between fivefactor personality traits and specific health-related personality dimensions. Int J Clin Health Psychol. 2012; 12(3): 373-387. 5. Kotov R, Gamez W, Schmidt F, Watson D. Linking “big” personality traits to anxiety, depressive, and substance use disorders: a meta-analysis. Psychol Bull. 2010; 136(5): 768-821. 6. Körner A, Geyer M, Gunzelmann T, Brähler E. Persönlichkeitsmerkmale über 60-Jähriger im Kontext sozio-demographischer Faktoren [The influence of socio-demographic factors on personality dimensions in the elderly]. Zeitschr Gerontol Geriatr. 2003; 36(2): 130-137. 7. Perry JC, Körner AC. Impulsive phenomena, the impulsive character (der triebhafte Charakter) and DSM personality disorders. J Pers Disord. 2011; 25(5): 586-606. 8. De Fruyt F, De Bolle M, McCrae RR, Terracciano A, Costa PT Jr. Assessing the universal structure of personality in early adolescence: The NEO-PI-R and NEO-PI-3 in 24 cultures. Assess. 2009; 16(3): 301-311. list of abbreviations N Neuroticism E Extraversion O Openness to Experience A Agreeableness C Conscientiousness NEO-PI NEO Personality Inventory NEO-PI-R NEO Personality Inventory-Revised NEO-PI-3 NEO Personality Inventory-3 NEO-FFI NEO Five-Factor Inventory NEO-FFI-R NEO Five-Factor Inventory-Revised NEO-FFI-3 NEO Five-Factor Inventory-3 NEO-FFI-30 30-item version of the NEO Five-Factor Inventory Acknowledgements We wish to thank Dipl.-Math. Gabriele Schmutzer for her support with the statistical analysis. REFERENCES 1. Carver CS, Connor-Smith J. Personality and coping. Annu Rev Psychol. 2010; 61: 679-704. 2. Vollrath M. Personality and stress. Scand J Psychol. 2001; 42(4): 335-347. 9. John OP, Naumann LP, Soto CJ. Paradigm shift to the integrative big five trait taxonomy. In: Oliver P, John RWR, Pervin LA, editors. Handbook of Personality, Third Edition: Theory and Research. New York: Guilford Press; 2008: 114-158. 10. Hong RY, Paunonen SV, Slade HP. Big five personality factors and the prediction of behavior: a multitrait-multimethod approach. Pers Ind Diff. 2008; 45(2): 160-166. 11. Yang J, McCrae RR, Costa PT, Dai XY, Yao SQ, Cai TS, et al. Cross-cultural personality assessment in psychiatric populations: The NEO-PI-R in the People’s Republic of China. Psychol Assess. 1999; 11(3): 359-368. 12. Costa PT Jr, McCrae RR. The Five-Factor Model and the NEO Inventories. In: Butcher JN, editor. Oxford Handbook of Personality Assessment. New York: Oxford University Press; 2009: 299-322. 13. McCrae RR, Costa PT Jr. A contemplated revision of the NEO Five-Factor Inventory. Pers Ind Diff. 2004; 36(3): 587-596. 14. McCrae RR, Costa PT Jr. Brief versions of the NEO-PI-3. J Ind Diff. 2007; 28(3): 116-128. 15. McCrae RR, Harwood TM, Kelly SL. The NEO Inventories. In: Harwood TM, Beutler LE, Groth-Marnat G, editors. Integrative Assessment of Adult Personality, 3rd ed. Guilford Press; 2011: 252-275. 16. Borkenau P, Ostendorf F. NEO-Fünf-Faktoren-Inventar nach Costa und McCrae (NEO-FFI) - Manual [NEO Five-Factor Inventory (NEO-FFI) by Costa and McCrae - Manual], 2nd ed (rev). Göttingen: Hogrefe; 2008. [AQ3. Please give page numbers for chapter, as above] Archives of Psychiatry and Psychotherapy, 2015; 1 : 21–32 28 Annet Körner et al. 17. Crede M, Harms P, Niehorster S, Gaye-Valentine A. An evaluation of the consequences of using short measures of the Big Five personality traits. J Pers Soc Psychol. 2012; 102(4): 874-888. 18. Körner A, Geyer M, Roth M, Drapeau M, Schmutzer G, Albani C, et al. Persönlichkeitsdiagnostik mit dem NEO-5-FaktorenInventar: Die 30-Item-Kurzversion (NEO-FFI-30) [Personality assessment with the NEO-Five-Factor Inventory: The 30Item-Short-Version (NEO-FFI-30)]. Psychother Psychosom Med Psych. 2008; 58: 238-245. 19. Hinz A, Brähler E, Geyer M, Körner A. Urteilseffekte beim NEO-FFI [Response sets measured with NEO-FFI]. Diagnostica. 2003; 49(4): 157-163. 20. Völzke H, Alte D, Schmidt CO, Radke D, Lorbeer R, Friedrich N, et al. Cohort profile: the study of health in Pomerania. Int J Epidemiol. 2011; 40(2): 294-307. 21. von Collani G, Grumm M. On the dimensional structure of personality, ideological beliefs, social attitudes, and personal values. J Ind Diff. 2009; 30(2): 107-119. 22. Reif A, Nguyen TT, Weissflog L, Jacob CP, Romanos M, Renner TJ, et al. DIRAS2 is associated with adult ADHD, related traits, and co-morbid disorders. Neuropsychopharmacol. 2011; 36(11): 2318-2327. 23. Meyer B, Shemla M, Schermuly CC. Social category salience moderates the effect of diversity faultlines on information elaboration. Small Group Res. 2011; 42(3): 257-282. 24. Grumm M, von Collani G. Measuring Big-Five personality dimensions with the implicit association test - Implicit personality traits or self-esteem? Pers Ind Diff. 2007; 43(8): 2205-2217. 25. Schlede N. Cognitive and behavioral disturbances in nonAlzheimer patients - an interdisciplinary project. 2009. 26. Sakalli B. Use of the NEO-FFI-30 at the Centre for Psychological Psychotherapy, Psychological Institute of the University of Heidelberg, Germany. Personal communication; 2009-03-01. 27. ADM Arbeitskreis Deutscher Markt- und Sozialforschungsinstitute e.V. Declaration for the Territory of the Federal Republic of Germany concerning the ICC/ESOMAR International Code of Market and Social Research. Frankfurt am Main, Germany: ADM Arbeitskreis Deutscher Markt- und Sozialforschungsinstitute e.V.; 2012. 30. Körner A, Drapeau M, Albani C, Geyer M, Schmutzer G, Brähler E. Deutsche Normierung des NEO-Fünf-FaktorenInventars (NEO-FFI) [German Norms for the NEO-Five Factor Inventory]. Zeits Med Psychol. 2008; 17: 133-144. 31. Costa PT Jr, McCrae RR. Revised NEO Personality Inventory (NEO-PI-R) and NEO Five-Factor Inventory (NEO-FFI) Professional Manual. Odessa, FL: Psychological Assessment Resources; 1992. 32. Borkenau P, Ostendorf F. NEO Fünf-Faktoren-Inventar (NEOFFI) nach Costa und McCrae (Handanweisung) [NEO FiveFactor Inventory (NEO-FFI) by Costa and McCrae (Manual)]. Göttingen: Hogrefe; 1993. 33. Körner A, Geyer M, Brähler E. Das NEO-Fünf-Faktoren Inventar (NEO-FFI): Validierung anhand einer deutschen Bevölkerungsstichprobe [The NEO Five-Factor Inventory (NEOFFI): Validation based on a German population sample]. Diagnostica. 2002; 48: 19-27. 34. Wiggins JS. The multivariate paradigm. In: Wiggins JS, editor. Paradigms of Personality Assessment. New York: Guilford Press; 2005: 123-63. 35. McCrae RR, Costa PT Jr, Hrebickova M, Urbanek T, Martin TA, Oryol VE, et al. Age differences in personality traits across cultures: self-report and observer perspectives. Eur J Pers. 2004; 18(2): 143-157. 36. Lockenhoff CE, Terracciano A, Bienvenu O, Patriciu NS, Nestadt G, McCrae RR, et al. Ethnicity, education, and the temporal stability of personality traits in the East Baltimore epidemiologic catchment area study. J Res Pers. 2008; 42(3): 577-598. 37. Becker G. NEO-FFI scores in college men and women: A view from McDonald’s unified treatment of test theory. J Res Pers. 2006; 40(6): 911-941. 38. Schmitt DP, Realo A, Voracek M, Allik J. Why can’t a man be more like a woman? Sex differences in Big Five personality traits across 55 cultures. J Pers Soc Psychol. 2008; 94(1): 168-182. 39. Costa PT Jr, Terracciano A, McCrae RR. Gender differences in personality traits across cultures: robust and surprising findings. J Pers Soc Psychol. 2001; 81(2): 322-331. 40. Rammstedt B. The 10-Item Big Five Inventory - Norm values and investigation of sociodemographic effects based on a German population representative sample. Eur J Psychol Assess. 2007; 23(3): 193-201. 28. World Medical Association. Declaration of Helsinki, 4th (Somerset West) Amendment. Somerset West, South Africa: World Medical Association; 1996. 29. Koch A. ADM-Design und Einwohnermelderegister-Stichprobe. Stichproben bei mündlichen Bevölkerungsumfragen [ADM-design and population registry samples. In-person surveys in the general population]. In: Gabler S, Hoffmeyer-Zlotnik JHP, Krebs D, editors. Gewichtung in der Umfragepraxis. Opladen: Westdeutscher Verlag; 1994: 99-116. Archives of Psychiatry and Psychotherapy, 2015; 1 : 21–32 Eicient and valid assessment of personality traits APPENDIx Table 4. Percentile Ranks for the NEO-FFI-30 Scales in the Population Sample Raw Score 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 M SD Neuroticism n=1,895 2.0 4.2 7.0 11.0 16.0 22.0 29.8 39.2 47.2 55.8 64.1 71.3 78.2 83.3 86.7 90.5 93.6 95.7 96.9 98.3 98.9 99.3 99.6 99.8 100.0 9.10 4.59 Extraversion n=1,896 0.1 0.1 0.2 0.4 0.8 1.7 3.2 5.9 8.5 12.9 19.9 27.7 35.9 46.6 57.3 68.5 77.4 85.7 91.6 94.6 96.5 98.2 99.2 99.6 100.00 13.68 3.74 Openness n=1,894 0.1 0.6 1.2 2.0 3.1 4.3 6.3 9.3 13.5 20.4 30.1 41.2 54.6 65.1 73.8 82.4 87.6 91.9 94.8 96.5 97.8 98.9 99.3 99.6 100.00 12.26 3.81 Note. M = mean total sum over all items of the subscale Archives of Psychiatry and Psychotherapy, 2015; 1 : 21–32 Agreeableness n=1,895 0.1 0.1 0.1 0.1 0.2 0.3 0.5 0.9 2.6 4.2 6.8 10.6 16.1 21.6 27.9 34.7 44.1 53.4 64.4 75.9 82.9 89.0 93.9 97.7 100.0 16.72 3.90 Conscientiousness n=1,897 0.1 0.1 0.1 0.2 0.2 0.5 1.3 2.0 2.6 3.9 6.3 10.3 14.3 18.7 23.9 31.6 40.8 54.2 66.4 76.6 84.0 90.2 96.0 100.0 17.76 3.75 29 Annet Körner et al. 30 Table 5. Percentile Ranks by Sex for the Subgroup of 18 to 33-year-old Individuals Raw score 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 M SD N 2.2 4.4 9.3 14.2 19.9 27.0 35.8 43.8 52.2 61.1 70.8 80.1 85.4 88.1 90.3 92.5 94.2 95.6 96.5 98.7 99.1 99.6 100.0 100.0 100.0 8.39 4.49 E 0.0 0.0 0.0 0.0 0.0 0.4 1.3 2.7 4.0 5.8 9.7 15.9 20.4 27.4 44.7 54.0 65.0 76.1 88.1 92.5 95.6 97.8 98.2 99.1 100.0 15.01 3.41 Males n=226 O 0.4 1.3 3.1 5.3 5.3 6.2 8.4 10.7 15.1 19.1 27.1 40.4 52.9 62.2 72.9 81.3 85.3 89.8 93.8 95.1 97.8 98.7 98.7 99.6 100.0 12.29 4.23 A 0.0 0.0 0.0 0.0 0.4 0.9 1.3 2.2 4.4 7.6 11.6 19.1 24.4 32.9 40.9 49.3 58.7 69.3 77.3 86.2 90.2 95.1 98.2 99.1 100.0 15.31 3.93 C 0.0 0.0 0.0 0.0 0.0 0.0 0.4 1.3 2.2 3.6 7.1 11.1 13.8 19.1 28.0 35.1 44.9 53.8 67.6 78.2 84.9 90.2 96.4 99.1 100.0 16.63 3.71 N 0.8 1.2 2.0 4.9 11.0 18.4 22.9 31.8 42.0 53.5 60.4 68.2 75.5 80.4 84.9 89.0 92.2 93.9 95.1 96.7 97.1 98.4 99.6 99.6 100.0 9.80 4.50 E 0.0 0.0 0.0 0.0 1.2 2.4 3.3 4.1 6.1 9.0 15.9 21.6 26.9 34.7 45.3 59.2 72.2 80.0 87.8 91.8 93.9 95.9 98.9 100.0 100.0 14.50 3.81 Females n=245 O 0.0 0.4 0.8 1.2 2.4 4.5 5.3 7.8 12.2 19.2 26.1 36.7 50.2 59.6 67.3 77.1 84.9 90.6 93.9 94.7 96.7 98.4 99.6 99.6 100.0 12.71 3.90 A 0.0 0.0 0.0 0.0 0.0 0.0 0.4 2.4 4.5 5.7 6.9 9.8 17.1 21.6 27.8 35.1 46.1 56.7 68.2 80.0 88.2 91.8 95.5 98.4 100.0 16.44 3.81 C 0.0 0.4 0.4 0.4 0.8 0.8 0.8 1.6 1.6 2.9 3.7 6.5 11.8 15.1 22.0 29.0 41.2 49.4 65.7 76.3 85.7 91.8 94.7 98.0 100.0 16.99 3.60 Note. N = Neuroticism; E = Extraversion; O = Openness to Experience; A = Agreeableness; C = Conscientiousness; M = mean total sum over all items of the subscale Table 6. Percentile Ranks by Sex for Subgroup of 34 to 49-year-old Individuals Raw score 0 1 2 3 4 5 6 7 8 Males Females n=249 N 2.8 7.6 12.0 16.5 22.1 27.7 39.8 47.0 53.0 E 0.0 0.0 0.4 0.8 0.8 1.6 3.6 7.7 10.8 O 0.4 0.8 1.2 3.6 4.4 7.2 10.0 14.1 18.5 A 0.4 0.4 0.4 0.4 0.4 0.4 0.8 1.2 2.8 C 0.0 0.0 0.0 0.0 0.4 0.4 0.8 1.2 2.8 n=328 n=329 n=330 n=330 n=329 N 0.9 2.7 4.0 7.9 13.7 17.4 23.5 33.5 42.1 E 0.0 0.0 0.0 0.0 0.3 0.9 2.4 5.2 7.9 O 0.0 0.6 0.9 1.5 2.4 3.0 4.6 7.9 12.2 A 0.0 0.0 0.0 0.0 0.0 0.3 0.3 0.3 2.4 C 0.0 0.0 0.0 0.0 0.3 0.3 0.9 1.2 1.8 Table continues on the next page Archives of Psychiatry and Psychotherapy, 2015; 1 : 21–32 Eicient and valid assessment of personality traits 31 9 56.6 14.1 24.5 5.6 2.8 50.6 11.6 18.2 3.3 3.0 10 65.1 17.7 33.3 10.4 3.2 59.1 16.1 28.6 6.4 4.8 11 71.5 21.7 43.4 12.9 6.4 65.5 25.5 37.7 11.6 7.6 12 78.3 28.5 54.6 20.5 10.4 75.3 35.0 50.2 17.3 12.1 13 83.5 37.8 64.7 24.9 15.3 80.5 45.6 62.6 21.9 16.7 14 85.5 47.4 71.5 32.1 18.5 85.7 53.8 72.3 27.4 20.3 15 89.2 61.4 80.7 39.8 24.5 90.2 64.7 80.2 35.6 23.9 16 94.0 69.9 85.5 48.6 28.9 93.0 74.8 86.0 43.8 33.6 17 95.2 80.7 90.4 55.4 43.8 95.1 86.0 89.7 55.9 41.2 18 96.8 88.4 92.4 69.9 54.6 96.3 89.4 94.5 64.7 55.8 19 98.8 94.0 94.4 79.9 66.3 97.9 92.4 96.4 75.1 67.3 20 99.2 96.0 95.2 84.3 77.9 98.8 95.4 97.6 83.0 77.6 21 99.6 97.6 98.0 91.6 81.9 99.1 97.9 98.2 90.0 87.3 22 99.6 98.4 98.0 96.0 87.6 99.4 99.4 99.7 94.8 90.3 23 100.0 98.8 98.4 98.0 94.4 99.4 99.7 100.0 99.1 96.7 24 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 M 8.59 14.22 12.15 13.23 17.78 9.68 13.96 12.55 16.67 17.57 SD 4.97 3.99 4.42 4.05 3.86 4.50 3.71 3.76 3.83 3.82 Note. N = Neuroticism; E = Extraversion; O = Openness to Experience; A = Agreeableness; C = Conscientiousness; M = mean total sum over all items of the subscale Table 7. Percentile Ranks by Sex for Subgroup of 50 to 65-year-old Individuals Raw Score 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 M SD N 5.1 7.2 11.0 16.9 23.2 30.0 39.7 50.6 59.1 67.5 75.9 79.7 84.0 88.6 89.9 93.2 95.8 97.9 98.3 98.7 98.7 99.2 99.6 100.0 100.0 7.90 4.56 E 0.0 0.0 0.0 0.0 0.8 1.3 2.1 3.4 4.2 10.5 20.3 29.1 37.1 52.3 61.2 74.7 82.7 88.6 93.7 95.8 96.6 98.3 99.6 100.0 100.0 13.48 3.88 Males n=237 O 0.0 0.4 0.8 0.8 2.5 3.8 5.1 7.2 11.8 21.9 31.6 40.5 54.4 65.4 73.0 82.7 86.5 90.7 94.9 97.0 98.3 99.2 99.2 99.6 100.0 12.33 3.72 A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.1 3.4 5.5 10.5 14.8 20.7 27.8 35.4 45.6 55.3 65.4 75.1 83.1 87.8 93.7 97.0 100.0 16.77 3.81 C 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.8 1.7 1.7 1.7 3.8 7.6 9.7 13.5 17.3 24.5 31.2 47.3 60.3 70.9 79.3 88.2 94.5 100.0 18.46 3.50 N 1.0 2.1 4.2 6.6 10.1 14.6 21.6 32.1 38.3 47.0 55.4 65.5 72.5 78.4 82.9 87.8 91.3 94.4 96.5 98.3 99.3 99.3 99.3 99.7 100.0 10.02 4.47 E 0.3 0.3 0.3 0.3 1.0 1.7 3.5 7.0 9.8 15.0 21.3 30.3 39.4 53.0 66.2 76.7 83.6 91.3 95.8 96.9 98.3 99.3 99.7 99.7 100.0 13.09 3.50 Females n=287 O 0.0 0.0 0.7 1.0 2.4 2.8 5.2 8.0 13.2 21.6 30.0 42.5 56.8 68.6 79.8 87.1 90.9 94.4 95.5 97.6 99.3 100.0 100.0 100.0 100.0 12.02 3.39 A 0.0 0.0 0.0 0.0 0.3 0.3 0.7 1.0 2.4 3.1 4.2 7.3 12.2 16.4 21.3 25.1 33.8 43.9 53.0 69.3 77.0 83.3 90.2 95.8 100.0 17.59 3.88 C 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.7 1.4 1.7 3.1 4.5 8.0 11.8 14.6 19.9 27.2 33.8 42.5 56.1 67.2 75.6 84.7 95.1 100.0 18.52 3.72 Note. N = Neuroticism; E = Extraversion; O = Openness to Experience; A = Agreeableness; C = Conscientiousness; M = mean total sum over all items of the subscale Archives of Psychiatry and Psychotherapy, 2015; 1 : 21–32 Annet Körner et al. 32 Table 8. Percentile Ranks by Sex for Subgroup of Individuals over 65 Years of Age Raw Score Males Females n=138 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 M SD N 2.9 6.5 9.4 11.6 13.8 23.9 32.6 44.2 53.6 64.5 70.3 80.4 85.5 90.6 92.8 94.2 95.7 97.8 98.6 98.6 100.0 100.0 100.0 100.0 100.0 8.33 4.16 E 0.7 0.7 0.7 2.9 3.6 5.1 5.8 10.1 13.0 19.6 31.9 42.0 53.6 66.7 73.9 81.9 87.0 90.6 94.9 97.8 98.6 99.3 99.3 99.3 100.0 12.21 3.87 O 0.0 1.4 1.4 1.4 2.9 2.9 5.1 11.6 13.0 18.1 31.9 45.7 60.1 68.8 74.6 84.8 90.6 94.2 96.4 98.6 98.6 99.3 99.3 100.0 100.0 11.99 3.60 A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.7 2.9 5.8 8.0 11.6 23.2 29.0 33.3 40.6 44.9 60.9 73.9 84.1 89.1 94.9 97.1 100.0 17.00 3.72 C 0.0 0.0 0.0 0.0 0.0 0.0 0.7 2.9 3.6 4.3 4.3 6.5 10.9 16.7 18.8 25.4 29.0 38.4 58.0 67.4 76.1 84.8 90.6 93.5 100.0 17.69 3.92 n= 185 N 1.1 3.2 7.0 11.9 15.1 20.5 27.0 35.1 43.2 52.4 62.2 66.5 73.5 81.6 85.4 90.3 94.1 97.8 98.4 98.9 100.0 100.0 100.0 100.0 100.0 9.35 4.47 n= 186 E 0.0 0.0 0.0 0.0 0.0 1.6 4.9 9.7 15.7 22.2 35.7 45.4 57.8 67.0 76.8 83.8 90.3 95.1 97.3 98.4 99.5 100.0 100.0 100.0 100.0 11.99 3.35 n= 184 O 0.0 0.0 0.5 0.5 2.2 3.8 7.6 8.7 12.0 19.6 34.2 47.3 63.6 72.3 80.4 87.0 93.5 97.8 98.4 99.5 100.0 100.0 100.0 100.0 100.0 11.71 3.18 n= 185 A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.6 2.7 3.8 7.6 11.4 17.3 23.2 35.1 41.1 54.6 66.5 73.0 82.7 87.6 96.8 100.0 17.95 3.53 n= 185 C 0.0 0.0 0.0 0.0 0.0 0.0 0.5 1.6 1.6 2.2 3.2 3.8 7.0 9.7 13.4 16.1 20.4 33.9 44.1 60.8 73.7 81.2 91.4 96.2 100.0 18.39 3.45 Note. N = Neuroticism; E = Extraversion; O = Openness to Experience; A = Agreeableness; C = Conscientiousness; M = mean total sum over all items of the subscale Archives of Psychiatry and Psychotherapy, 2015; 1 : 21–32