It's a terrible metric that fails basic dimensional analysis. Anytime you see a ratio of logs, you should already be suspicious. Say algorithm A is twice as f

It's a terrible metric that fails basic dimensional analysis. Anytime you see a ratio of logs, you should already be suspicious. Say algorithm A is twice as fast as algorithm B. Then we'll have alpha r/R log(T)/log(t). The alpha r/R is constant, so the only interesting part is log(T)/log(t) = log(2t)/log(t) = log2/log(t) + 1. We can make this apparently unitless number take any value we want just by changing the unit used to measure time (or if a unit were fixed, by changing the amount of data used to test). It's sort of vaguely superficially sensible, but the idea of being able to reduce comparison of compression algorithms (which fundamentally trade off speed for compression ratio) to a 1-dimensional value is laughable. Charles Bloom's Pareto frontier charts (http://cbloomrants.blogspot.com/2015/03/03-02-15-oodle-lz-pareto-frontier.html http://cbloomrants.blogspot.com/2015/03/03-02-15-oodle-lz-pa...) are one of the more reasonable options.