Pearson Correlation Coefficient (PCC)

The Pearson Correlation Coefficient or PCC is the degree of correlation between two variables X and Y. Here the PCC is used to assert the similarity between expression profiles. The PCC ranges from -1 to 1 where 1 indicates perfect correlation between variables, 0 indicates no-correlation and -1 is perfect anti-correlation. When constructing co-expression networks 0.7 is used as a cutoff value for PCC values.