Aim of the study:
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.

Subject or material and methods:
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.

Discussion:
In sum, the 30-item-version of the NEO-FFI constitutes an assessment tool comparable to the full-length instrument regarding psychometric properties.

Conclusions:
In sum, the 30-item-version of the NEO-FFI constitutes an assessment tool comparable to the full-length instrument regarding 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.