tl;dr: Almost none. For the details, read on.
As most of you know, every year for three years now I’ve tried to identify everyone hired into a N. American tenure-track asst. professor position in ecology or an allied field such as fish & wildlife. One reason I do this is to provide information and context to faculty job seekers. Faculty job seeking is stressful enough already, for good reason: there’s a lot of competition for tenure-track faculty jobs. I think it’s a shame for faculty job seekers to also get stressed about job market rumors and speculation, which tend to flourish in the absence of good information.
Today: the worry that someone who applied for the same faculty position as you might have the inside track by virtue of already being a collaborator with someone in the hiring department. How common is it for tenure-track asst. professor positions in ecology to be filled by someone with a pre-existing collaboration with someone in the hiring department?
According to my unscientific Twitter poll, a decent number of people think it’s common, or at least not vanishingly rare. 23% think that >10% of newly-hired ecology asst. profs had previously co-authored at least one paper with someone in the hiring dept. An additional 17% think that 6-10% of new hires did so.
The correct answer, or at least the best estimate of the correct answer based on the data I’ve compiled so far, is ~0%. I’ve gone through the Google Scholar pages of 35 people hired into N. American tenure-track asst. professor positions in ecology and allied fields advertised on ecoevojobs.net in 2017-18, not including the rare people who were currently employed in some other capacity by the hiring institution at the time of their hiring. I checked the addresses of everyone with whom the new hires have co-authored. I have yet to find anybody who’s co-authored a paper with someone in the department that hired them, but wasn’t already employed by the department that hired them.
Now, this is a haphazard rather than a random sample. It’s skewed towards new hires with fewer papers, because they’re quicker to check (compiling data on this is time-consuming…). But the sample does include some people with dozens of papers, and it includes hires at the full range of institutions, from tiny teaching colleges to huge research universities. So I don’t think my sample is too unrepresentative. And it’s not a huge sample. But FWIW, if (say) 10% of new hires have co-authored a paper with someone in the hiring dept., then there’s only about a 3% chance that a random sample of 35 new hires would fail to include anyone who’d co-authored a paper with someone in the hiring dept.* Even if only 6% of new hires have previously co-authored a paper with someone in the hiring department, there’s still only an 11% chance that none of them would be included in a random sample of 35 new hires. So although I’m sure the true number isn’t literally 0%, <1% is the best guess based on the available data, and anything >6% or so is fairly unlikely.
This lines up with my own anecdotal experience, and the experience of the people I’ve spoken to who’ve sat on search committees or been interviewed for ecology faculty positions recently. In my experience, and in the experience of the people with whom I’ve spoken, it’s fairly rare for those being interviewed to have previously met anyone in the hiring dept., never mind collaborated with them. It also lines up with other considerations. Many new ecology faculty are hired into teaching colleges where faculty do little or no research, or into departments in which they’re the only person working in their research area. It’s no surprise that those hires have never collaborated with anyone in the hiring department before being hired. And the vast majority of newly-hired ecology faculty are <6 years post-PhD and have done only one or two postdocs. They rarely have geographically-extensive collaboration networks. Most of them have only ever co-authored with their graduate and postdoctoral supervisors, their current and former labmates, and maybe with ecologists at a few other institutions. About the only way they could be hired into a department where they have a pre-existing collaboration would be for them to be hired into a department where they currently work or have worked in the past. Which happens in only 2-4% of all tenure-track ecology hires at the asst. professor level. Finally, profs don’t like anything that smacks of nepotism on the part of their colleagues, and they don’t want faculty searches conducted for the personal benefit of any one current faculty member. Any prof who tries to steer a faculty search towards hiring one of their current collaborators is likely to get a lot of pushback from their departmental colleagues.
I hope this data provides some useful context for you faculty job seekers out there.
*3% is the percentage of the time you would expect to get 0 successes in 35 Bernoulli trials with a per-trial success probability of 10%.
No newly-hired tenure-track asst. profs of ecology were hired where they got their PhDs (scroll down to the footnotes)