Evaluation Metrics
ˇ Precision = Positive Predictive
Value
l “ratio of the number of relevant
documents retrieved over the total
number of documents retrieved”
l how much extra stuff did you get?
ˇ Recall = Sensitivity
l “ratio of relevant documents retrieved
for a given query over the number of
relevant documents for that query in
the database”
l how much did you miss?
TP
TP+FP
TP
TP+FN