On Testability and Goodness of Fit Tests in Missing Data Models

Razieh Nabi, Rohit Bhattacharya

Keywords: Missing data DAGs, causal graphs, missing not at random, Verma constraints, identification, odds ratio parameterization, estimating equations

Abstract: Significant progress has been made in developing identification and estimation techniques for missing data problems where modeling assumptions can be described via a directed acyclic graph. The validity of results using such techniques rely on the assumptions encoded by the graph holding true; however, verification of these assumptions has not received sufficient attention in prior work. In this paper, we provide new insights on the testable implications of three broad classes of missing data graphical models, and design goodness-of-fit tests for them. The classes of models explored are: sequential missing-at-random and missing-not-at-random models which can be used for modeling longitudinal studies with dropout/censoring, and a no self-censoring model which can be applied to cross-sectional studies and surveys.