Interpreting physical and behavioral health scores from new work disability instruments.
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)).


METHODS
Cross-sectional, secondary data from 3 independent samples to develop and validate the functional levels for physical and behavioral health functioning.


METHODS
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.


CONCLUSIONS
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.
Boston University School of Public Health, Health and Disability Research Institute, 715 Albany Streeet, T5W Boston, MA 02118, USA. emarfeo@bu.edu.
Elizabeth E
EE
Marfeo
Pengsheng
P
Ni
Leighton
L
Chan
Elizabeth K
EK
Rasch
Christine M
CM
McDonough
Diane E
DE
Brandt
Kara
K
Bogusz
Alan M
AM
Jette
D000328:Adult; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D006233:Persons with Disabilities / Q000523:psychology / Q000534:rehabilitation*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods; D011594:Psychometrics; D012919:Social Behavior; D014937:Work; D014938:Work Capacity Evaluation; D055815:Young Adult