We've started sending emails out for the survey I'm doing with the Dutch scientists. We started by sending out just over 500 of the SkS emails. Around 10% of them bounced, presumbably stale emails. That's not an unusual proportion, in fact a little low compared to other experiences I've had with mailouts. Emails go stale at a startling rate and the fact that we are dealing with papers up to 20 years old means it's not unexpected. I'm hoping to get the bounced email information so I can tag those emails in our database.

That's actually better than I might have guessed at.

UK postdoctoral contracts only last 2-3 years in most cases. I know plenty of people who move around every few years for their next contract until they settle down.