Measurement Invariance of Scores on the Somatic Symptom Scale-8: National Sample of Non-Clinical Adults in the United States

Abstract

Objective

The aim of the present study was to test the factorial invariance and convergent validity evidence of scores on the Somatic Symptom Scale (SSS)-8 with a national sample of adults living in the United States.

Method

A data collection contracting service was hired to recruit a national, non-clinical sample (N = 821) of adults in the United States stratified by the census data for age, gender, ethnicity, and geographic location.

Results

Factorial invariance testing via multiple-group confirmatory factor analysis revealed strong factorial invariance evidence (configural, metric, and scalar) of SSS-8 scores across gender, ethnicity, help-seeking history, education, and income. Convergent validity testing displayed strong correlations between SSS-8 scores and the following established measures: Patient Health Questinaire-9, Generalized Anxiety Disorder-7, and Mental Health Inventory-5.

Conclusion

Collectively, the results suggest that professional counselors can use the SSS-8 to enhance somatic symptomology screening efforts with adults living in the United States.

SOCIAL SIGNIFICANCE STATEMENT

Somatic symptoms (physical health issues that cause mental distress) are a considerable concern among U.S. adults. We found reliability (consistency) and validity (test scores measured what they were designed to measure) evidence for U.S. adults’ scores on the SSS-8. Results supported the utility of the SSS-8 for monitoring somatic symptoms.

Keywords:

• Assessment
• somatic symptoms
• counseling
• adults in the United States
• SSS-8

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under grant number P20GM103451.