Gains Charts

Charts can be displayed on the Gains tab as an alternative to tables.

  1. On the Gains tab, select the Quantiles icon (third from left on the toolbar). (Charts are not available for node-by-node or cumulative statistics.)
  2. Select the Charts icon.
  3. Select the displayed units (percentiles, deciles, and so on) from the drop-down list as desired.
  4. Select Gains, Response, or Lift to change the displayed measure.

Gains Chart

The gains chart plots the values in the Gains (%) column from the table. Gains are defined as the proportion of hits in each increment relative to the total number of hits in the tree, using the equation:

(hits in increment / total number of hits) x 100%

The chart effectively illustrates how widely you need to cast the net to capture a given percentage of all the hits in the tree. The diagonal line plots the expected response for the entire sample, if the model were not used. In this case, the response rate would be constant, since one person is just as likely to respond as another. To double your yield, you would need to ask twice as many people. The curved line indicates how much you can improve your response by including only those who rank in the higher percentiles based on gain. For example, including the top 50% might net you more than 70% of the positive responses. The steeper the curve, the higher the gain.

Lift Chart

The lift chart plots the values in the Index (%) column in the table. This chart compares the percentage of records in each increment that are hits with the overall percentage of hits in the training dataset, using the equation:

(hits in increment / records in increment) / (total number of hits / total number of records)

Response Chart

The response chart plots the values in the Response (%) column of the table. The response is a percentage of records in the increment that are hits, using the equation:

(responses in increment / records in increment) x 100%