Talk:Fold change

egads this could be so much better...

Question: When I think of folding a paper in half, I think of doubling the thickness. That is, a single fold causes 2 times the thickness. 2 folds would cause 4 times the thickness. This is why I've always thought that fold chance was exponential. An initial value of 1 would undergo a 3 fold increase to get to 4. Does that make sense? Maybe I just have an issue with the etymology of the situation... — Preceding unsigned comment added by 172.11.57.208 (talk) 17:53, 7 December 2014 (UTC)[reply]

I also assumed fold originated as powers of 2 and I kind of still need convincing that it wasn't always used in that way in the distant past. Sure one can see how someone would assume that such a word came from a time period where the idea of exponentials was difficult, but the analogy with literal folding made the idea more clear. Surely blacksmiths and bakers would have naturally tended to the powers of 2 meaning for such a word.

This article really need to distinguish ratios, fractional increases and decreases, and log2 fold change in a way that addresses both the mathematical and colloquial English language perspectives. Some people will assume a one fold decrease means halving (as in a piece of paper), but that is only true for log2 fold changes. JeremyLeipzig (talk) 18:48, 8 January 2016 (UTC)[reply]

if "Oxford English Dictionary[1] and Merriam-Webster Dictionary,[2] as well as Collins's Dictionary of Mathematics," all agree that e.g. four-fold increase = 4 times as much; and the first two of those are pretty much the accepted definitions of English in the UK and the USA, then where is this article getting its information to the contrary? Jofuone (talk) 19:04, 9 February 2017 (UTC)[reply]

This is possibly the most misleading page on Wikipedia and has moved me to make my first comment! A fold change is defined as B/A almost everywhere as detailed by the numerous references included in the page. The (B-A)/A version is completely unreferenced and a perfunctory google search can find no mention of this definition anywhere. I would recommend reversing the entire article, and having B/A as the main definition with a note at the bottom saying "other usages" and the (B-A)/A included (or just removed as it is unreferenced) 46.208.194.151 (talk) 18:18, 7 June 2018 (UTC)Dwood[reply]