MAR (Missing At Random)

Missing At Random (MAR) is a statistical concept describing situations where the probability of missing data depends only on observed information, not on the unseen or missing data itself. For example, if older participants are less likely to answer a survey question, and age is recorded, then the missing responses are related to known information. MAR allows researchers to make valid inferences by adjusting for the observed data, reducing bias caused by missing information. Importantly, MAR assumes that the reason for missing data can be explained using existing, observed data, making the analysis more reliable.