Identifiable Generative Models for Missing Not at Random Data Imputation
- URL: http://arxiv.org/abs/2110.14708v1
- Date: Wed, 27 Oct 2021 18:51:38 GMT
- Title: Identifiable Generative Models for Missing Not at Random Data Imputation
- Authors: Chao Ma and Cheng Zhang
- Abstract summary: Many imputation methods do not take into account the missingness mechanism, resulting in biased imputation values when MNAR data is present.
In this work, we analyze the identifiability of generative models under MNAR.
We propose a practical deep generative model which can provide identifiability guarantees under mild assumptions.
- Score: 13.790820495804567
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: Real-world datasets often have missing values associated with complex
generative processes, where the cause of the missingness may not be fully
observed. This is known as missing not at random (MNAR) data. However, many
imputation methods do not take into account the missingness mechanism,
resulting in biased imputation values when MNAR data is present. Although there
are a few methods that have considered the MNAR scenario, their model's
identifiability under MNAR is generally not guaranteed. That is, model
parameters can not be uniquely determined even with infinite data samples,
hence the imputation results given by such models can still be biased. This
issue is especially overlooked by many modern deep generative models. In this
work, we fill in this gap by systematically analyzing the identifiability of
generative models under MNAR. Furthermore, we propose a practical deep
generative model which can provide identifiability guarantees under mild
assumptions, for a wide range of MNAR mechanisms. Our method demonstrates a
clear advantage for tasks on both synthetic data and multiple real-world
scenarios with MNAR data.
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