Measurement Properties of the Nordic Questionnaire for Psychological and Social Factors at Work: A Rasch Analysis

Area of Science:

• Occupational Health Psychology
• Psychometrics
• Rehabilitation Science

Background:

• The Nordic Questionnaire for Psychological and Social Factors at Work (QPS Nordic) is used to assess psychosocial factors in the workplace.
• Evaluating the measurement properties of instruments like the QPS Nordic is crucial for accurate assessment in research and clinical settings.
• Psychosocial factors such as demand, control, and support are important in understanding work-related health outcomes, particularly for individuals with conditions like back pain.

Purpose of the Study:

• To evaluate the measurement properties of the Nordic Questionnaire for Psychological and Social Factors at Work (QPS Nordic), specifically its domains of demand, control, and social support.
• To assess the unidimensionality and targeting of the QPS Nordic domains using Rasch analysis.
• To examine the invariance of the QPS Nordic measures across different demographic and clinical variables.

Main Methods:

• Rasch analysis using RUMM 2030 software was employed to evaluate the QPS Nordic.
• Data were collected from 226 subjects with back pain at a one-year follow-up.
• The analysis focused on the demand, control, and social support domains (30 items) of the QPS Nordic.

Main Results:

• Rasch analysis indicated disordered thresholds in 25 out of 30 items, suggesting potential areas for revision.
• The domains of demand, control, and support demonstrated adequate fit to the Rasch model when analyzed separately.
• While the demand domain was well-targeted, patients with current neck and back pain reported lower control and higher support than measured by the questions. Differential item functioning (DIF) by gender was found in two items; other invariances were documented.

Conclusions:

• The demand, control, and support domains of the QPS Nordic are unidimensional constructs with adequate measurement properties for assessing psychological and social factors at work.
• Despite some item-level issues and specific patient group characteristics, the QPS Nordic domains demonstrate utility in research involving individuals with back pain.
• Further refinement of specific items may enhance the precision of the QPS Nordic for capturing psychosocial work factors.