We recently noticed that in some situations, parentheses in a ratio formula indicator could override the typically-desired weighted average behavior that DevResults defaults to and generate an unweighted average. This has been fixed.
Normally, in a simple ratio like A/B, adding (unnecessary) parentheses like (A/B) would have no affect on the order of operations. Unfortunately our parser was interpreting these accessory parentheses as an indication that the user wanted to consider the average as equally weighted, where a small sample and a large sample were averaged together as though they were equal in size. Typically, this is not what DevResults users prefer.
Only a small number of clients were affected, and only a small subset of those clients' formulas were potentially affected. We'll be reaching out shortly to those in that camp.
Meanwhile, going forward you can trust that both A/B and (A/B) will both give weighted averages. If for some reason you actually did want to generate an unweighted average, there is still a way to achieve this — just reach out to us on Helpdesk to find out [spoiler alert: follow the pattern 1 * (A/B)].