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Addressing Ceiling Effects in Health Status Measures: A Comparison of Techniques Applied to Measures for People with HIV Disease
Author(s) -
Huang IChan,
Frangakis Constantine,
Atkinson Mark J.,
Willke Richard J.,
Leite Walter L.,
Vogel W. Bruce,
Wu Albert W.
Publication year - 2008
Publication title -
health services research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.706
H-Index - 121
eISSN - 1475-6773
pISSN - 0017-9124
DOI - 10.1111/j.1475-6773.2007.00745.x
Subject(s) - ceiling (cloud) , disease , ceiling effect , medicine , human immunodeficiency virus (hiv) , health services research , gerontology , environmental health , econometrics , public health , alternative medicine , family medicine , geography , nursing , mathematics , pathology , meteorology
Objectives. To compare different approaches to address ceiling effects when predicting EQ‐5D index scores from the 10 subscales of the MOS‐HIV Health Survey. Study Design. Data were collected from an HIV treatment trial. Statistical methods included ordinary least squares (OLS) regression, the censored least absolute deviations (CLAD) approach, a standard two‐part model (TPM), a TPM with a log‐transformed EQ‐5D index, and a latent class model (LCM). Predictive accuracy was evaluated using percentage of absolute error ( R 1 ) and squared error ( R 2 ) predicted by statistical methods. Findings. A TPM with a log‐transformed EQ‐5D index performed best on R 1 ; a LCM performed best on R 2 . In contrast, the CLAD was worst. Performance of the OLS and a standard TPM were intermediate. Values for R 1 ranged from 0.33 (CLAD) to 0.42 (TPM‐L); R 2 ranged from 0.37 (CLAD) to 0.53 (LCM). Conclusions. The LCM and TPM with a log‐transformed dependent variable are superior to other approaches in handling data with ceiling effects.