In detail, specificity(X) = 1 – (entropy(X) / log2(N) ), where X is a vector of sample-average expression values for an enhancer over all facets (cell types and organs/tissues were analyzed separately) and N its cardinality (|X|, the number of facets). The same calculations were done for TPM and RLE normalized CAGE-derived expression levels of RefSeq protein-coding gene promoters (TSS +/− 500 bp).
