Direct and flexible marginal inference for semicontinuous data.
The marginalized two-part (MTP) model for semicontinuous data proposed by Smith et al. provides direct inference for the effect of covariates on the marginal mean of positively continuous data with zeros. This brief note addresses mischaracterizations of the MTP model by Gebregziabher et al. Additionally, the MTP model is extended to incorporate the three-parameter generalized gamma distribution, which takes many well-known distributions as special cases, including the Weibull, gamma, inverse gamma, and log-normal distributions.
1 Center for Health Services Research in Primary Care, Durham VAMC, Durham, NC, USA.
Valerie A
VA
Smith
2 Department of Biostatistics, University of North Carolina, Chapel Hill, NC, USA.
John S
JS
Preisser
D056808:Biostatistics / Q000379:methods; D003627:Data Interpretation, Statistical; D006801:Humans; D015233:Models, Statistical; D012044:Regression Analysis
Generalized gamma; log-skew normal; marginalized models; two-part models; zero-inflation