How to Check Missing Data Using Little's MCAR Test

Introduction

This article describes how to tests the null hypothesis that missing data is Missing Completely At Random (MCAR). A p.value of less than 0.05 is usually interpreted as being that the missing data is not MCAR (ie, is either Missing At Random or non-ignorable).

Requirements

A Displayr document with a data set.

Method

1. Go to Anything > Data > Missing Data > Little's MCAR Test.
2. Under Inputs > Variables select the variables you want to analyze, change any other settings, and click Calculate to run the function.

OPTIONAL: You can adjust the following settings to modify the calculation and output:

• Output
  • Summary - Shows a nicely formatted table of the test results (default).
  • R - The original text-based output from the LittleMCAR function.
• Variable names - Display Variable Names in the output, instead of Variable Labels.
• More decimal places - Display numeric values with 8 decimal places.
• Filter - The data is automatically filtered using any filters prior to estimating the model.

Technical details:

This test starts by using the EM algorithm to estimate the means and covariances. These estimates are approximate, and, consequently, the test is also approximate (it may get slightly different results on different computers).

This test does not take weights into account.