Assessing measurement properties of two single-item general health measures.
BACKGROUND
Multi-item health status measures can be lengthy, expensive, and burdensome to collect. Single-item measures may be an alternative. We compared measurement properties of two single-item, general self-rated health (GSRH) questions to assess how well they captured information in a validated, multi-item instrument.


METHODS
We administered a general health survey (SF-12V) that included "standard" and "comparative" forms of a GSRH. We repeated the survey two weeks later to the same 75 medically stable outpatients to test for GSRH reproducibility, reliability, and validity using SF-12V Physical Functioning and Emotional Health subscales as a reference.


RESULTS
At each survey administration, the two GSRH questions demonstrated good alternate forms reliability (first administration: r = 0.74, p < 0.001; second administration: r = 0.74, p < 0.001) and good reproducibility ("standard": ICC 0.69; "comparative": ICC 0.85). Both GSRH items correlated with physical functioning ("standard": r = 0.66; "comparative": r = 0.56) and emotional health measures ("standard": r = 0.65; "comparative": r = 0.59). Mean subscale measures associated with responses in each GSRH category were significantly different (ANOVA, p < 0.001), indicating strong discriminant scale performance.


CONCLUSIONS
Our single-item, GSRH questions demonstrated good reproducibility, reliability, and strong concurrent and discriminant scale performance with an established health status measure.
Section of General Internal Medicine and Geriatrics, Tulane University Health Sciences Center, New Orleans, LA 70112, USA. kdesalv@tulane.edu
Karen B
KB
DeSalvo
William P
WP
Fisher
Ky
K
Tran
Nicole
N
Bloser
William
W
Merrill
John
J
Peabody
D000328:Adult; D000368:Aged; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D011795:Surveys and Questionnaires / Q000592:standards*; D014481:United States