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This document discusses essential considerations in measuring classification performance focusing on data selection, evaluation techniques, and reliability of outcomes. It highlights the significance of using appropriate training and test datasets, exploring methods like Resubstitution, Hold-out, Leave-one-out, K-fold cross-validation, and Bootstrap approaches. Each technique is examined for its advantages and disadvantages, particularly concerning the size of the dataset and trustworthiness of performance estimates.
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1. Measuring Classification Performance D. Pokrajac 2003
2. Main Issues What Data to use?
How to measure performance?
How do we trust our measured results?
3. What data to use? Typically we learn our model on some data set, known as training set
Subsequently, we evaluate, model on dataset known as test set
Main issue: given available data, how to generate training and test set
4. Major technique to choose test set Re-substitution
Hold-out
Leave-one-out
K-fold cross validation
Bootstrap
5. Re-substitution Use all available data for training set
Test set=training set=available dataset
Problems:
If available data set is small our results on unseen data will be poor
Estimation of actual performance can be poor
6. Hold-Out Split available dataset into two halves Use one half for training set and the other for test set Problem: Poor use of data (half data discarded from training!)