The samples were taken from a random selection of 100 of the top 1000 firms. The real question is how to make that selection of 100 firms so that statistically the sample size is a representative sampling. The goal is not to determine whether or not the jobs are available to those folks who may have just been laid off. The goal is to determine just how many job opening do exist in the Fortune 1000 without needing to hit every single job board of every one of those 1000 companies... surely there is a statistician who can solve that one? ;-)