7.3 SENSITIVITY AND SPECIFICITY
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Sensitivity measures the ability of the model to classify a record positively, while specificity measures the ability to classify a record negatively. Sensitivity measures what proportion of all positive records are captured by your model, while specificity measures what proportion of all the negative records are captured by your model. Of course, a perfect classification model would have sensitivity = 1.0 = 100%. However, a model which simply classified all customers as positive would also have sensitivity = 1.0. Clearly, it is not sufficient to identify the positive responses alone. A classification model also needs to be specific, meaning that it should identify a high proportion of the customers who are negative. Of course, a perfect classification...