Statistical Methods for Multivariate Missing Data in Health Survey Research.

Kim, Dong Kee; Park, Eun Cheol; Sohn, Myong Sei; Kim, Han Joong; Park, Hyung Uk; Ahn, Chae Hyung; Lim, Jong Gun; Song, Ki Jun

Original Article

Korean Journal of Preventive Medicine 1998;31(4): 875-884.

Dong Kee Kim, Eun Cheol Park, Myong Sei Sohn, Han Joong Kim, Hyung Uk Park, Chae Hyung Ahn, Jong Gun Lim, Ki Jun Song

¹Department of Biostatistics, Yonsei University College of Medicine, Korea.
²Department of Preventive Medicine and Public Health, Yonsei University College of Medicine, Korea.

ABSTRACT

Missing observations are common in medical research and health survey research. Several statistical methods to handle the missing data problem have been proposed. The EM algorithm (Expectation-Maximization algorithm) is one of the ways of efficiently handling the missing data problem based on sufficient statistics. In this paper, we developed statistical models and methods for survey data with multivariate missing observations. Especially, we adopted the Em algorithm to handle the multivariate missing observations. We assume that the multivariate observations follow a multivariate normal distribution, where the mean vector and the covariance matrix are primarily of interest. We applied the proposed statistical method to analyze data from a health survey. The data set we used came from a physician survey on Resource-Based Relative Value Scale(RBRVS). In addition to the EM algorithm, we applied the complete case analysis, which used only completely observed cases, and the available case analysis, which utilizes all available information. The residual and normal probability plots were evaluated to access the assumption of normality. We found that the residual sum of squares from the EM algorithm was smaller than those of the complete-case and the available-case analyses.

Key words: Missing data; Multivariate normal data; EM algorithm; Biostatistics; Resource-Based Relative Value Scale