The current "why" is " The Portal Team is curious as to how many of the visitors to the Portal page do not have English set as their preferred browser language." That doesn't seem right to me, since we can already answer it based on logging. I suspect the real "why" is more like "The portal team would like to know if users are more likely to click on a language link if languages relevant to them are in a more prominent position."
Topic on Talk:Wikipedia.org Portal A/B testing
Agree, the rationale and test descriptions do not match. Ideally, we need to describe what decision would the test influence (i.e. "do we want to arrange languages differently depending on user's language?") and then say how we decide if to take that decision or not (e.g. "if we see that rearranging improves clickthrough rates then we conclude rearranging is good thing and we'll add it to portal").
We'd like to know if re-arranging the links around the globe increases click-through for the top 10 links. The idea is that if the user does not have English as their preferred browser language, we'll put their preferred language into a more visible area for them to click on (if they can't read English). The thought that we'd really like to prove is that if the browser lists a language that is not part of our top 10 language links - that user will click through more frequently to their preferred language and not have to use the language by article links to get to a page that they can read easily.
I've updated this test's WHY section.
The second half looks good now (yay!), but I still don't like/understand the first half as it sits. How about "The Portal Team is curious whether Portal visitors who do not have English set as their preferred browser language would be more likely to take an action (click through to a wiki site) if their preferred language link is in a more prominent and visible position." ?
I think that's what it says now in the first half? I might have updated it after you posted this comment? :(
The text still says the test will tell us "how many" users don't have English, but that's information we already have access to. My proposed rewording is similar at a glance, but different.
Updated now, thanks!