Threshold adjustment

The decision threshold is a very important concept to keep track of. By default, we have the following:

• Prediction probability >= 0.5 implies Class 1
• Prediction probability < 0.5 implies Class 0

However, the threshold is a powerful meta-parameter that we are free to adjust. Table 5.3 shows predictions from a model versus the true labels.

If we use the default threshold of 0.5, the accuracy is 2/4 = 50%. If, on the other hand, the threshold chosen is 0.80, the accuracy is 100%. This shows how important the chosen threshold can be:

Predicted Output	True Output
0.65	0
0.75	0
0.85	1
0.95	1

Table 5.3 – A table showing the predicted...