> Variability is a qualitative setting that indicates how much light levels vary in the zone, i.e. the dynamic range of light landing on surfaces.
> By the nature of the situation being modeled, the user knows whether to expect a high degree of variability in the lighting or a low one.
Given those two phrases, 'a high or low degree of variability in the lighting' translates as 'a high or low degree of dynamic range' — or would be likely to, given human abbreviation tendencies, in successive works and conversations.
"Making global illumination user-friendly" (Ward, 1995) https://radsite.lbl.gov/radiance/papers/erw95.1/paper.html
> Variability is a qualitative setting that indicates how much light levels vary in the zone, i.e. the dynamic range of light landing on surfaces.
> By the nature of the situation being modeled, the user knows whether to expect a high degree of variability in the lighting or a low one.
Given those two phrases, 'a high or low degree of variability in the lighting' translates as 'a high or low degree of dynamic range' — or would be likely to, given human abbreviation tendencies, in successive works and conversations.