title: XGBoost: why does test error increase when train error decreases in XGBoost?
body: <p>When I train the model by xgboost and I find "eval-merror" is increasing and "train-merror" is decreasing as below;is something in error?</p>
  
  <p><a href="https://i.stack.imgur.com/29VZu.png" rel="nofollow noreferrer">enter image description here</a></p>