CH 19 Interpret Model

4 types of impacts of features on target

  1. Overall impact of a feature without consideration of impact of other features
  1. Overall impact of a feature with consideration of impacts of other features
  1. Directional impact of a feature
  1. Partial impact of a feature

examined as logistic regression from target, full green bar = at least 30% of target value

logloss = importance score

predictive value

Randomly shuffle values in one feature then evaluate performance

Whether presence of a value increases predictive ability

red bars indicate feature values that make positive cases more likely blue bars indicate feature values that make negative cases more likely

frequency vs. features

effects= coefficients

power of language

word cloud= words with highest coefficients

intensity of color = higher coefficient

stop word = assumed to have little value

Insights screen is key

hotspot screen shows most relevant combo of features and effects on target

Reason Codes evaluates individual level

left and right thresholds allow to change probability

left (blue) = 0-.22 right (red) = .585-1.0