Rarely. For details, read on.
Junior applicants for faculty positions open to applicants of multiple ranks sometimes worry that senior applicants have a big advantage over junior applicants. Personally, I don’t think they do. Senior applicants are held to higher standards than junior applicants–a cv that is impressive for a postdoc is not impressive for an associate or full professor. Senior applicants also are more expensive to hire (higher salary, more startup), and there’s a greater risk that they’ll turn down the offer after negotiating a counter-offer from their current institution. Finally, senior candidates are “known quantities”, and many hiring institutions prefer the “potential” of junior candidates.
But we don’t just have to rely on anecdotal impressions; we can look at data.
A while back I googled publicly-available information, emailed colleagues and department chairs, and asked around on social media, to try to identify who was hired for pretty much all tenure-track faculty positions in ecology and allied fields advertised in N. America in 2016-17 on ecoevojobs.net. I didn’t consider any positions that weren’t open to hiring at the asst. professor level. I ID’d who was hired for about 200 positions (note that not everyone I identified was an ecologist). 25 of the positions for which I was able to identify who was hired were advertised as “assistant/associate” or “open rank”. Only 2 of those 25 (both in the same department) were filled at the associate level. The rest were filled at the assistant level. In addition, there was one position that was advertised at the assistant level but filled at the associate level, and a second position that was advertised at the assistant level but that may have been filled at the associate level.
Obviously, I have no idea who applied for those positions, so I can’t tell you everything you might possibly want to know about why those searches played out as they did. But the important take home is that it’s rare for ecology faculty positions that could be filled at the assistant professor level to be filled at a higher rank instead.
I bet these data come as a surprise to some of you. A few days back I did an unscientific little Twitter poll, and out of 70 respondents 23% guessed that ecology positions advertised as “asst/assoc” or “open rank” are filled at a rank above asst. more than 20% of the time. That suggests to me that there’s a non-trivial number of ecologists out there who really overestimate how often senior candidates apply for faculty positions that could be filled at the junior level, and/or overestimate how competitive senior candidates typically are for such positions.