Select an alternative model from Discover Key Predictors with TreeNet^® Regression

Run Predictive Analytics Module > TreeNet® Regression > Discover Key Predictors. Select Select Alternative Model in the results.

Note

This command is available with the Predictive Analytics Module. Click here for more information about how to activate the module.

Overview

When you use Discover Key Predictors to remove the least important predictors, Minitab Statistical Software produces results for the model with the best value of the accuracy criterion for the analysis, such as the maximum R² value. Minitab lets you explore other models from the sequence that led to the identification of the optimal model. Generally, you select an alternative model if another model has a value of the criterion close to the best, but with fewer predictors. A model with fewer predictors is easier to interpret, can have better prediction accuracy, and allows you work with a smaller number of predictors.

For example, the following model selection table has 20 steps. The model with the maximum R² value has 5 predictors and occurs at step 16. The model at step 17 has an R² value that is lower by less than 0.1. The model at step 17 has 4 predictors. The full results from the model at step 17 are also of interest.

Model Selection by Eliminating Unimportant Predictors

Test

Model	Optimal Number of Trees	R-squared (%)	Number of Predictors	Eliminated Predictors
1	300	89.32	21	None
2	300	89.34	19	Plastic Flow Rate, Change Position
3	300	89.39	18	Drying Temperature
4	300	89.46	17	Melt Temperature Zone 2
5	300	89.51	16	Plastic Temperature
6	300	89.50	15	Formula
7	300	89.59	14	Hold Pressure
8	300	89.57	13	Screw cushion
9	300	89.69	12	Melt Temperature Zone 4
10	300	89.70	11	Back Pressure
11	300	89.86	10	Melt Temperature Zone 1
12	300	89.90	9	Drying Time
13	300	89.92	8	Temperature at Measurement
14	300	90.06	7	Melt Temperature Zone 5
15	300	90.16	6	Melt Temperature Zone 3
16*	300	90.23	5	Screw Rotation Speed
17	300	89.96	4	Injection Temperature
18	297	79.37	3	Cooling Temperature
19	244	66.64	2	Injection Pressure
20	164	46.19	1	Machine

Perform the analysis

Click Select Alternative Model in the output. A dialog box opens that shows a plot of the criterion against the number of eliminated predictors and a table that summarizes the steps.

Compare the criteria

To select an alternative model, click a point on the graph or a row in the table. Press Display Results to create the results for that model.

Once you display the results, you can click a button in the output to tune the hyperparameters of the model or to make predictions from the model. For more information, go to Select hyperparameter values to evaluate from the results for TreeNet® Regression or Predict new results for Fit Model and Discover Key Predictors with TreeNet® Regression.

Tip

To compare the output of two different analyses or reports, right-click the second item in the Navigator and choose Open in Split View.