An irrelevant feature is an input attribute with little or no association with the target and little useful information for the prediction task. In tabular data, it adds noise rather than reliable signal. section 2.2.3
Assess candidate features before retaining them:
- Use domain knowledge to rule out features that are implausible sources of information. section 2.2.3
- Apply simple univariate tests, such as correlation or chi-square analysis, as an initial statistical check. section 2.2.3
- Build a model, reshuffle each feature, and compare performance; features whose randomization changes little are likely irrelevant or redundant. section 2.2.3
- Drop features that contribute no useful signal to reduce false disturbances, memory use, and training and prediction time. section 2.2.3
Randomization check
Train a model on the available features, randomly replace the values of one feature, and observe the change in predictive performance. Little change suggests that the feature can be removed, although the same result may indicate redundant information elsewhere. section 2.2.3
