About 1/3, as of 2013. For details, read on.
UPDATE: I see from the Twitter machine that I need to clarify something: just because I’m posting on the question in the post title doesn’t mean I think that TT jobs are the only worthwhile jobs for PhD-holding ecologists. Because I emphatically do not think that! For instance see here and here. In general, I try to write my posts very carefully to say exactly what I mean, without implying anything about my views on any other matter. So please don’t leap to any conclusions about what I think about topic X based on what I do or don’t say about some other topic Y. If you want to know what I think about X, ask me in the comments. 🙂 /END UPDATE
I backed that answer out of the data in an excellent paper, Hampton & Labou (2017). The data come from NSF’s Survey of Doctoral Recipients, a huge stratified random sample of doctoral recipients in all scientific and engineering fields, including ecology.
According to Hampton & Labou, 4826 people got US PhDs in ecology from 2000-2011. Note that these are PhDs in “ecology” specifically, not any of the other allied fields in which some ecologists get PhDs (e.g., fisheries, wildlife, botany, etc.). It’s hard to say if or how that skews the results, though it shouldn’t skew them too much since PhD recipients in ecology outnumber those in most allied fields in the NSF doctoral program classification system. As of 2013, 10.8% of those 4826 people were postdocs and 3.5% were involuntarily unemployed. Hampton & Labou focus most of their analysis on the remaining 85.7% of employed non-postdocs, which they say in Table 1 is “~3800 individuals”. Which I don’t quite understand, since 85.7% of 4826 is 4136 people, not ~3800. I’m not sure why there’s a discrepancy, but the explanation is probably some minor misunderstanding of the data on my part.* But whatever, it’s not a big discrepancy and doesn’t make much difference for purposes of this post. So anyway, Table 1 in Hampton & Labou says that 40.6% of 2000-2011 ecology PhD recipients who were employed and weren’t postdocs were in tenured or tenure-track faculty positions as of 2013. So let’s do the math: (0.406×3800)/4826 = 0.319, meaning 31.9% of people who got ecology PhDs from 2000-2011 were in tenured or tenure-track faculty positions as of 2013. Or, if you use 4136 rather than 3800 as the number of employed non-postdoc ecologists in 2013 who got PhDs from 2000-2011, you get (0.406×4136)/4826 = .348, i.e. 34.8% of 2000-2011 ecology PhDs were in tenured or tenure-track faculty positions as of 2013. So, as of 2013, about 1/3 of people who’d received US ecology PhDs from 2000-2011 were in tenured or tenure-track faculty positions.
I recognize that that number may not be exactly the number you want to know. For instance, it is not the odds that a “typical” ecology faculty job seeker will attain a tenure-track position, for two reasons. First, the data analyzed above includes some unknown number of ecology PhD recipients who didn’t end up in a tenure-track faculty position because they never sought one. Rather, they aimed for some non-faculty career from the get-go. Second, the data analyzed above include some people who hadn’t attained tenure-track faculty positions as of 2013 but who subsequently went on to do so. So 1/3 is probably a lower bound on the odds that a “typical” ecology faculty job seeker will attain a tenure-track faculty position.
Which is broadly consistent with another line of evidence. Recently, I showed that, in recent years, about 42% of anonymous ecology faculty job seekers on ecoevojobs.net reported receiving at least one tenure-track faculty job offer in a given year. If 42% of ecology faculty job seekers receive at least one tenure-track offer each year, the cumulative fraction who receive and accept at least one tenure-track offer presumably is somewhat higher than 42%. Though perhaps not a lot higher because some offers are declined, and because different people have different odds of receiving an offer. 42% is greater than 1/3, so the ecoevojobs.net data are broadly consistent with the lower bound of 1/3 calculated above.**
In conclusion, the statistics you sometimes read that only a very small fraction of PhD recipients (<10%) go on to tenure-track faculty positions are for different or broader fields than “ecology”. They don’t apply to ecology specifically. About 1/3 of recent-ish ecology PhD recipients have gone on to tenure-track faculty positions. Which implies that the “prior probability” that a “typical” ecology faculty job seeker will eventually attain a tenure-track faculty position in ecology is at least a bit higher than that, though perhaps not a lot higher.*** Of course, your own individual odds of obtaining a tenure-track faculty position in ecology could be considerably higher or lower than that, because everyone’s own situation is unique in some ways.
As always, I provide these data in the hopes that they provide some useful information and context to ecology faculty job seekers. I am not trying to make anyone feel either happy or sad about their prospects of obtaining a tenure-track faculty position in ecology. Nor am I trying to either encourage or discourage anyone from seeking a tenure-track faculty position in ecology. Whether to seek a faculty position, and how you feel about that choice, are both very personal matters. My hope is that I’m helping you make whatever choice is best for you, and I wish you all the best whatever path you choose.
*Is the discrepancy because in Table 1 Hampton & Labou aren’t counting people employed in med schools or pre-college educational institutions? Is it because some US ecology PhD recipients leave the country and so leave the survey for purposes of tracking their subsequent employment? Something else?
**Of course, the self-selected people who list their faculty job search outcomes on ecoevojobs.net might not be representative of all ecology faculty job seekers. Any sampling biases here probably aren’t massive, for reasons described here. But there definitely could be some sampling bias, and so perhaps 42% is a bit of an overestimate of the fraction of ecology faculty job seekers receiving a tenure-track offer in a given year. But that’s ok for our purposes, because even if somewhat less than 42% of ecology faculty job seekers receive a tenure-track offer in a given year, that would still be consistent with at least 1/3 of them eventually attaining a tenure-track job.
***Some of you may wonder if US ecology faculty job market has changed dramatically since 2013, so that the data in this post are no longer at all representative of the current state of play. I doubt that, because the number of people receiving ecology PhDs each year doesn’t vary that much from year to year, and nor does the number of advertised tenure-track ecology faculty positions. So I doubt the ratio of ecology faculty job seekers to ecology faculty jobs is very different now than it typically was during the period of time covered by Hampton & Labou’s data. But sure, things could be a bit different now. Note that, if things are a bit different now on the US ecology faculty job market than the Hampton & Labou data indicate, I wouldn’t assume they’re worse. I say that because the Hampton & Labou data include the Great Recession and its immediate aftermath, a period during which many tenure-track faculty searches were canceled. Meaning that the ratio of ecology faculty job seekers to ecology faculty jobs may well have jumped. Possibly, the odds that a “typical” ecology faculty job seeker will attain a tenure-track ecology faculty job are now a bit higher than the Hampton & Labou data would suggest, because we’re now a decade past the Great Recession. Or they could be a bit lower; it’s hard to say. I just wouldn’t confidently assume that the odds must be lower now than the Hampton & Labou data suggest.