Suppose the doors to the lab featured a disclaimer for new graduate students saying: “Warning: years of hard work inside, with no guarantee of a career.” Some might think twice before entering. Although many graduate students recognize the pitfalls of striving for a position in academia, others still remain idealistic about their prospects.

At least one laboratory's website now offers a measured dose of reality (http://www.biology.duke.edu/johnsenlab/advice.html). “Before you apply to this lab or any other,” writes Sönke Johnsen on his group's website, “there are a few things to keep in mind.” Johnsen, an associate biology professor at Duke University in Durham, North Carolina, stresses that graduate school in biology is not a sure path to success nor is it a certainty that students will achieve a career similar to that of their adviser. He underscores this argument by doing the maths. On average, a professor at a research university looks after 3 students at a time for about 5 years each, which equates to 18 students over a 30-year career. Given that the total number of academic positions has stayed roughly constant in recent years, these 18 people are, in effect, competing for one job.

Should more labs post such disclaimers? Quite possibly, given the positive response Johnsen's note has received from contributors at http://www.scienceblogs.com. No wise adviser would allow for false promises or false hope — although lab heads should also be sure to emphasize that PhD scientists, especially those open to non-academic jobs, are generally quite employable.

Johnsen goes on to offer another reality check, albeit one related more to quality of life than job openings. Make sure to pursue your passions, he writes, before committing to an intense five or six years in the lab. And make sure that you don't commit to a miserable, yet high-profile, lab on the assumption that the pay-off, half a dozen years down the line, will make it all worthwhile.

Once you've read and understood a disclaimer of this type, you're probably ready to walk through those doors.