# Precision, Recall, and PR Curve

I am doing research on binary classification. I have three classification models work on one data set. I have no True Positive, True Negative, False Positive, and False Negative metrics, each model produces value between 0 and 1. I calculate the four metrics: Root Mean Square Error (RMSE), Normalized Mean Square Error (NMSE), Mean Absolute Error (MAE), and Symmetric Mean Absolute Percentage Error (SMAPE) in order to find the accuracy of each model. I want now to calculate the Precision, Recall to draw the PR Curves and get the final verdict about the better classification model among the three models. Is there any way to calculate Precision and Recall, and draw PR Curve in terms of RMSE, NMSE, MAE, and SMAPE ? If not, what should I do to get True Positive, True Negative, False Positive, and False Negative values for each models? Naturally, they neither produce 0 or 1.

• Welcome to cross validated! But please expand your acronymns to give people who are not familiar with the acronyms a chance to answer. – cbeleites supports Monica Jan 29 '15 at 19:37

If you want a contingency table, you need to decide on a cut-off somewhere in $[0,1]$. ROC and PR curves essentially visualize all possible contingency tables your model can produce by computing tables at every cut-off. RMSE, MAE and co are all regression metrics, don't use those to assess classification models. It's quite easy to make perfect classifiers whose decision values would yield poor RMSE.