What is "Missing" in output of plot_tree API of XGBoost
The &quot;missing&quot; at the different nodes are the observations for which the feature on which the split is made is missing. E.g. if the value for TotalSubmissionGuidelines is below 0.5 or missing, then the observation follows the left path of the decision tree. XGBoost supports missing values by default and learns the branch direction during training, see the documentation.