A lot of times what you'll see done is structured more as a reorg than just a straight layoff, where if they need to trim $xM from the budget, they'll start shrinking and eliminating teams at the IC level until they reach .7-.8 of that figure, then see how many "extra" managers they have and start trimming there, typically just based on seniority rather than pay. Rinse and repeat until you're at .9-1.1x depending on how many people you think will resign after the layoffs.