$$Precision=\frac{\text{\# of unigrams matched}}{\text{\# of unigrams in generation}}$$$$Recall=\frac{\text{\# of unigrams matched}}{\text{\# of unigrams in reference}}$$$$F_{mean}=\frac{10\ast Precision\ast Recall}{9\ast Precision+Recall}$$$$Penalty=0.5\ast (\frac{\text{\# of minimum chunks where chunks are matched}}{\text{\# number of unigrams in the matched chunks}}{)}^3$$$$METEOR=F_{means}\ast (1-penalty)$$