Detect a "shift of mass" between two conditions. For example expression might move later in a time series in an experimental condition vs a control. If all expression shifted to a later time in the experimental condition, this would be given an effect size of 1. Conversely if all expression shifted to an earlier time, the effect size would be -1.

effect_shift(coef1, coef2)

effect_shift_stepdown(coef1, coef2)

effect_shift_stepup(coef1, coef2)

effect_shift_log2(coef1, coef2)

effect_shift_stepdown_log2(coef1, coef2)

effect_shift_stepup_log2(coef1, coef2)

Arguments

coef1

Column numbers in the design matrix for the first condition, in some meaningful order.

coef2

Corresponding column numbers for the second condition.

Value

An object defining how to calculate an effect size.

Details

This can be viewed as similar to Somers' D. effect_shift_log2 is adapted to work with log2 scaled coefficients. This is almost certainly the version you want.

Note that this effect size is not symmetric: effect_shift_log2(c(1,2),c(3,4)) and effect_shift_log2(c(1,3),c(2,4)) will give different results.

The _stepdown and _stepup versions are for cumulative distributions. These are most useful in group effect form, where they can be used to examine shifts in start or end of transcriptions from RNA-seq or microarray data.