Evaluating the Reliability and Model Fit of the 13-Item and 10-Item Big Five Inventory (Malay Version) among Malaysian Firefighters.

Background: Lengthy instruments for assessing personality traits may not be applicable in certain research settings. In situations where time is scarce, a briefer measurement is preferable. However, the reliability of a briefer measurement of the Big Five Inventory (BFI) among firefighters in Malaysia has not been reported. This study aimed to investigate the reliability and model fit of the Malay version of the BFI with 13 items (BFI-13) and 10 items (BFI-10) among Malaysian firefighters.

Methods: A cross-sectional study using cluster sampling was conducted in a state in Malaysia. Each respondent completed BFI-10 and BFI-13 using an online survey with a 1-month interval between each response. Reliability testing was evaluated using internal consistency and a 2-week interval test-retest. The model fit of these two BFI questionnaires was evaluated via confirmatory factor analysis (CFA).

Results: A total of 124 firefighters participated in the study, with a zero-dropout rate. The Malay version of BFI-13 exhibited higher reliability by displaying good internal consistency with Cronbach's alpha of 0.919, 0.838, 0.871 and 0.896 for the domains conscientiousness, neuroticism, agreeableness and extraversion, respectively, and acceptable test-retest reliability with moderate to good intraclass correlation (0.588-0.806). The CFA model also indicated that BFI-13 has a better model fit (comparative fit index [CFI] = 0.993; Tucker-Lewis index [TLI] = 0.991; standardised root mean squared residual [SRMR] = 0.029; root mean square error of approximation [RMSEA] = 0.035).

Conclusion: The Malay version of BFI-13 is reliable and applicable enough to be supplementarily used in surveys among Malaysian firefighters. By using a brief personality assessment, it will reduce the cognitive and emotional burden on respondents.