Stress Research Institute, Stockholm University, Stockholm, Sweden.
PLoS One. 2013 Aug 12;8(8):e70541. doi: 10.1371/journal.pone.0070541. eCollection 2013.
To examine the factor structure and to evaluate the longitudinal measurement invariance of the demand-control-support questionnaire (DCSQ), using the Swedish Longitudinal Occupational Survey of Health (SLOSH).
A confirmatory factor analysis (CFA) and multi-group confirmatory factor analysis (MGCFA) models within the framework of structural equation modeling (SEM) have been used to examine the factor structure and invariance across time.
Four factors: psychological demand, skill discretion, decision authority and social support, were confirmed by CFA at baseline, with the best fit obtained by removing the item repetitive work of skill discretion. A measurement error correlation (0.42) between work fast and work intensively for psychological demands was also detected. Acceptable composite reliability measures were obtained except for skill discretion (0.68). The invariance of the same factor structure was established, but caution in comparing mean levels of factors over time is warranted as lack of intercept invariance was evident. However, partial intercept invariance was established for work intensively.
Our findings indicate that skill discretion and decision authority represent two distinct constructs in the retained model. However removing the item repetitive work along with either work fast or work intensively would improve model fit. Care should also be taken while making comparisons in the constructs across time. Further research should investigate invariance across occupations or socio-economic classes.
使用瑞典纵向职业健康调查（SLOSH），检验需求-控制-支持问卷（DCSQ）的因子结构，并评估其纵向测量不变性。
在结构方程模型（SEM）框架内，采用验证性因子分析（CFA）和多群组验证性因子分析（MGCFA）模型，检验因子结构和跨时间的不变性。
CFA 在基线时确认了四个因素：心理需求、技能裁量、决策自主权和社会支持，通过删除技能裁量的重复工作项，获得了最佳拟合。还检测到心理需求中工作快和工作强度之间的测量误差相关性（0.42）。除了技能裁量（0.68），获得了可接受的综合可靠性度量。建立了相同因子结构的不变性，但需要谨慎比较随着时间推移的因子平均水平，因为缺乏截距不变性是明显的。然而，对于工作强度，建立了部分截距不变性。
我们的研究结果表明，在保留的模型中，技能裁量和决策自主权代表两个不同的结构。然而，删除重复工作项以及工作快或工作强度中的任何一项，都会提高模型拟合度。在跨时间比较结构时也应谨慎行事。进一步的研究应调查不同职业或社会经济阶层的不变性。
