Portuguese version of the Swedish Occupational Fatigue Inventory (SOFI) among assembly workers: Cultural adaptation, reliability and validity

Abstract

Objectives: Reliable and valid instruments are essential for understanding fatigue in occupational settings. This study analyzed the psychometric properties of the Portuguese version of the Swedish Occupational Fatigue Inventory (SOFI). Material and Methods: A cross-sectional study was conducted with 218 workers from an automotive industry involved in assembly tasks for fabrication of mechanical cables. Convergent and discriminant validity, internal consistency reliability and confirmatory factor analysis were performed. Results: Results showed adequate fit to data, yielding a 20-item, 5-factor structure (all intercorrelated): Chi 2 /df (ratio Chi 2 and degrees of freedom) = 2.530, confirmatory fit index (CFI) = 0.919, goodness of fit index (GFI) = 0.845, root mean square error of approximation (RMSEA) = 0.084. The SOFI presented an adequate internal consistency, with the sub-scales and total scale presenting good reliability values (Cronbach's α values from 0.742 to 0.903 and 0.943 respectively). Conclusions: Findings suggest that the Portuguese version of the SOFI may be a useful tool to assess fatigue and prevent work-related injuries. In future research, other instruments should be used as an external criterion to correlate with the SOFI dimensions. Int J Occup Med Environ Health 2017;30(3):407-417

Korean Version of the Swedish Occupational Fatigue Inventory among Construction Workers: Cultural Adaptation and Psychometric Evaluation

“…Moreover, the highest loaded items differed from the findings reported in the other SOFI translation studies [19,20]. Moreover, some items such as items 9 (drowsy), 12 (indifferent), and 20 (uninterested) displayed low loading values as compared to those present in previous studies [19][20][21]. In addition, our findings suggest a re-evaluation of the validity of lack of motivation and sleepiness by re-assessing "uninterested" and "indifferent" for lack of motivation and "drowsy" and "falling asleep" for sleepiness.…”

“…The Korean version of the SOFI displayed satisfactory internal consistency reliability, item-subscale reliability, and test-retest reliability, which are valuable metrics for newly developed instruments [31]. Our internal consistency coefficients indicated high levels of reliability for all items, which was similar to those of the Chinese (25 items) [20] and Portuguese (20 items) [21] versions and somewhat higher than that of the Spanish version (15 items) [19]. The item-subscale reliability was moderate to high and test-retest reliability was strong, similar to the original SOFI [18].…”

“…The reliability results are expected since all participants worked in the same occupation. Homogeneity of the sample may increase reliability because the respondents experience similar fatigue symptoms due to comparable tasks or working environments [20,21], as the original study discussed [18].…”

“…This instrument consists of five dimensions: physical exertion, physical discomfort, lack of motivation, sleepiness, and lack of energy [10,18]. The SOFI has been translated into several languages in many countries [19][20][21] and has been tested among diverse occupational groups [10,[18][19][20]. This study focused on construction workers who have physically demanding jobs and commonly shift work, both of which are highly associated with high levels of fatigue [20,22].…”

“…This study focused on construction workers who have physically demanding jobs and commonly shift work, both of which are highly associated with high levels of fatigue [20,22]. Considering the very diverse interpretation of fatigue among different individuals, occupational groups, and cultures [10,[18][19][20][21], it is necessary to develop a Korean version of the SOFI based on the cultural characteristics of Korea. The aims of this study were to describe the translation and cultural adaptation process of the Korean version of the SOFI, evaluate its psychometric properties by replicating the original model [18], and determine its utility among a sample of Korean construction workers.…”