John Mount explains the vtreat package that he and Nina Zumel have put together:
When attempting predictive modeling with real-world data you quicklyrun into difficulties beyond what is typically emphasized in machine learning coursework:
- Missing, invalid, or out of range values.
- Categorical variables with large sets of possible levels.
- Novel categorical levels discovered during test, cross-validation, or model application/deployment.
- Large numbers of columns to consider as potential modeling variables (both statistically hazardous and time consuming).
- Nested model bias poisoning results in non-trivial data processing pipelines.
Any one of these issues can add to project time and decrease the predictive power and reliability of a machine learning project. Many real world projects encounter all of these issues, which are often ignored leading to degraded performance in production.
vtreatsystematically and correctly deals with all of the above issues in a documented, automated, parallel, and statistically sound manner.
That’s immediately going onto my learn-more list.