Modeling Semicontinuous Longitudinal Expenditures: A Practical Guide.

Journal Article (Journal Article)

OBJECTIVE: To compare different strategies for analyzing longitudinal expenditure data that have a point mass at $0. We provide guidance on parameter interpretation, research questions, and model selection. DATA SOURCES, STUDY DESIGN, AND DATA COLLECTION: One-part models, uncorrelated two-part models, correlated conditional two-part (CTP) models, and correlated marginalized two-part (MTP) models have been proposed for longitudinal expenditures that often exhibit a large proportion of zeros and a distribution of continuous, highly right-skewed positive values. Guidance on implementing and interpreting each of these model is illustrated with an example of longitudinal (2000-2003) specialty care expenditures of veterans with hypertension, drawn from Veterans Administration data. PRINCIPAL FINDINGS: The four strategies answer different research questions, are appropriate for different structures of data, and provide different results. If there is a point mass at $0, then the MTP model may be most useful if the primary interest is in mean expenditures of the entire population. A CTP model may be most useful if the primary interest is in the level of expenditures conditional on them being incurred. CONCLUSIONS: Researchers should consider which modeling strategy for longitudinal expenditure outcomes is both consistent with research aims and appropriate for the data at hand.

Full Text

Duke Authors

Cited Authors

  • Smith, VA; Maciejewski, ML; Olsen, MK

Published Date

  • August 2018

Published In

Volume / Issue

  • 53 Suppl 1 / Suppl Suppl 1

Start / End Page

  • 3125 - 3147

PubMed ID

  • 29315527

Pubmed Central ID

  • PMC6056585

Electronic International Standard Serial Number (EISSN)

  • 1475-6773

Digital Object Identifier (DOI)

  • 10.1111/1475-6773.12815


  • eng

Conference Location

  • United States