Reputation: 135
I wonder how to compute precision and recall using a confusion matrix sentiment analysis multi-class classifier using Confusion Matrix. I have a dataset of 5000 texts and I did human labeling for a sample of 100. Now, I would like to compute the Precision and Recall for the classifier based on this sample of data. I have three classes; Positive, Neutral and Negative.
So how can I compute these metrics for each class?
As I am new here in stackoverflow, I couldn't illustrate the confusion matrix I have, so let us assume that we have the following confusion matrix:
red color > Negative
green color > Positive
purple color> Neutral
Upvotes: 2
Views: 3516
Reputation: 119
you can measure
precision=TPos/(TPos+TNeg+TNeu) i.e 30/(30+20+10)=50% ,
recall=TPos/(TPos+FNeg+FNeu) i.e 30/(30+50+20)=30% ,
F-measure=2*precision*recall/(precision+recall)=37.5% ,and
Accuracy(all true)/(all data) =30+60+80/300=56.7% .
for more http://blog.kaggle.com/2015/10/23/scikit-learn-video-9-better-evaluation-of-classification-models/
Upvotes: 3