Content » Vol 47, Issue 5

Original report

Interpreting physical and behavioral health scores from new work disability instruments

Elizabeth E. Marfeo, Pengsheng Ni, Leighton Chan, Elizabeth K. Rasch, Christine M. McDonough, Diane E. Brandt, Kara Bogusz, Alan M. Jette
Boston University School of Public Health, Health & Disability Research Institute, 715 Albany Streeet, T5W Boston, MA 02118, USA. E-mail:
DOI: 10.2340/16501977-1947


Objective: To develop a system to guide interpretation of scores generated from 2 new instruments measuring work-related physical and behavioral health functioning (Work Disability – Physical Function (WD-PF) and WD – Behavioral Function (WD-BH)).
Design: Cross-sectional, secondary data from 3 independent samples to develop and validate the functional levels for physical and behavioral health functioning.
Subjects: Physical group: 999 general adult subjects, 1,017 disability applicants and 497 work-disabled subjects. Behavioral health group: 1,000 general adult subjects, 1,015 disability applicants and 476 work-disabled subjects.
Methods: Three-phase analytic approach including item mapping, a modified-Delphi technique, and known-groups validation analysis were used to develop and validate cut-points for functional levels within each of the WD-PF and WD-BH instrument’s scales.
Results: Four and 5 functional levels were developed for each of the scales in the WD-PF and WD-BH instruments. Distribution of the comparative samples was in the expected direction: the general adult samples consistently demonstrated scores at higher functional levels compared with the claimant and work-disabled samples.
Conclusion: Using an item-response theory-based methodology paired with a qualitative process appears to be a feasible and valid approach for translating the WD-BH and WD-PF scores into meaningful levels useful for interpreting a person’s work-related physical and behavioral health functioning.

Lay Abstract


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