The claim is Price’s Law, originally an observation about academic publications in a field - half of them come from the square root of the number of contributor

The claim is Price’s Law, originally an observation about academic publications in a field - half of them come from the square root of the number of contributors, now taken as a general MBA style business rule of thumb. One which joins nicely with evaporative cooling, the idea that the top performers also have the most skills and experience because they are working harder, have the easiest time leaving for another job because they are the most driven and have the better work history to talk about, perhaps the most contacts from the more work done. And together, there is likely to be a big overlap between the most useful employees and the ones who have the easiest chance of leaving. Lose sqrt(employees) of people for any reason where they self select - e.g. cancelled bonuses, deathmarch project, austerity measures, return to the office - and it’s likely to hurt disproportionately.