Fig. 1.

CART model predicting past-year Pap testing with complexity parameter set to 0.011 (Chicago, 2010–2012).

Note: Decision tree models are interpreted based on both their overall performance in predicting the outcome accurately as well as individual terminal nodes that predict the outcome for specific subgroups of data. The “root node” of the decision tree displays the distribution of the outcome variable in the entire data set. Each subsequent “node” displays the next splitting variable, the number of participants represented by that node, and the percent of those participants with the outcome of interest. “Terminal nodes” display the outcome distribution (in this case, past-year Pap test) in final subgroups for which further splits would not improve prediction.