Showing posts with label split. Show all posts
Showing posts with label split. Show all posts

Friday, February 24, 2012

Avoid splitting trees by value missing

Hi, could anyone kindly let me know how to prevent the Decision Trees model from using value missing as a criterion to split trees?

Thanks,

hz

Decision trees only splits on missing if you have sparse data. Are you using nested tables possibly? If not, then you have a column in your table with enough NULLs that are correlated with your target that there is enough information gain to cause a split. You can use NOT NULL, but this will just prevent the model from processing altogether if nulls are present|||

Yes, unfortunately, there are a lot of null values. I am not sure what you mean by "use NOT NULL". I have many predictor columns. Their null values are not in sync. If "NOT NULL" is used as a filter for every predictor, there may be no case left.

|||Unfortunately there's no way to not split by a value that appears in the data in SQL 2005. It's something for us to think about for future versions (expecially the "NULL" case)

Avoid splitting trees by value missing

Hi, could anyone kindly let me know how to prevent the Decision Trees model from using value missing as a criterion to split trees?

Thanks,

hz

Decision trees only splits on missing if you have sparse data. Are you using nested tables possibly? If not, then you have a column in your table with enough NULLs that are correlated with your target that there is enough information gain to cause a split. You can use NOT NULL, but this will just prevent the model from processing altogether if nulls are present|||

Yes, unfortunately, there are a lot of null values. I am not sure what you mean by "use NOT NULL". I have many predictor columns. Their null values are not in sync. If "NOT NULL" is used as a filter for every predictor, there may be no case left.

|||Unfortunately there's no way to not split by a value that appears in the data in SQL 2005. It's something for us to think about for future versions (expecially the "NULL" case)