It would have been great if I could mass message those folks, but that was not possible for three reasons. First it was not readily technically possible (I am sure someone with more scripting skills like you could have slapped something together to do this, but it was not directly feasible for me. Two, there is a reason you can't mass message folks, people don't want to be spammed. I wanted to conduct the survey in as upright a means possible and for me that meant individually contacting members. Third, I actually had to do additional selection at this point. The 1740 included folks that did not mention their age, or said they were under 18. In accordance with my Human Subjects Approval I could only talk with adults.

So, I needed to manually contact folks, while it would have been possible for me to click through each of the 1740 members profile pages it was time prohibitive and sampling procedures could get the level of specificity that I needed. No need to bother everyone in the community.

So, starting on page 1 of search results I checked out the folks at the top of each page of search results. I then contacted the ones that fit the two remaining criteria. That is how I generated the sample of 160 members from the pool of 1740.

What was your exact method for randomly sampling?