|Higher-order metrics arising from combinations of the basic measures documented in Table1|
|Measure||Algebra formulae||Description||Example in skeletal muscle context|
|Phenotype Impact Factor||Average (normalized) expression of the i-th gene across the two conditions multiplied by its differential expression. In other words, PIF weights the differential expression of a given gene by its overall abundance.||MYL2 very strongly.|
|Regulatory Impact Factor, Option 1||For the i-th regulator and across all the j differentially expressed genes (j = 1, …, ndE) RIF1 looks at the average PIF of the i-th regulator weighted by the squared differential co-expression between the i-th regulator and the j-th differentially expressed gene. It addresses the question: Which regulator is consistently highly differentially co-expressed with the abundant differentially expressed gene?||MSTN very strongly.|
|Regulatory Impact Factor, Option 2||For the i-th regulator and across all the j differentially expressed genes (j = 1, …, ndE) RIF1 looks at the average change in predictive ability of the i-th regulator to predict the abundance of the j-th differentially expressed gene. It addresses the question: Which regulator has the most altered ability to predict the abundance of differentially expressed genes.||MSTN very strongly.|
Hudson et al.
Hudson et al. BMC Genomics 2012 13:356 doi:10.1186/1471-2164-13-356