Identification of Missing Mechanism in an Incomplete Two-Way Contingency Table with Two Supplemental Margins

• Activity Number: 680 - Imputation and Analysis of Missing Survey Data
• Type: Contributed
• Date/Time: Thursday, August 2, 2018 : 10:30 AM to 12:20 PM
• Sponsor: Survey Research Methods Section
• Author(s): Saebom Jeon*
• Companies: Mokwon University
• Keywords: MAR; MNAR; selection model; pattern mixture model; response odds; nonresponse odds

Abstract

For an incomplete two-way contingency table including units missing cases, we propose a new identification rule for missing mechanisms using cell probabilities concerning missing data. We firstly introduce a variable-based missing mechanism to clarify the missing mechanism in two-way contingency tables in general selection and pattern mixture models. Next, we suggest two missing ratios to show the non-identifiability between missing-at-random and missing-not-at-random, as well as to characterize the missing mechanism. Simulation studies show that the missing mechanism criterion works well for large samples.