It depends. Usually we try to use multiple methods of recruiting so we can put together a diverse sample. We’ll either snowball and have a primary contact who will point us to people we can talk to, and/or we’ll just go out to wherever it makes sense to find the sort of people we are looking for—and yes, we’re always surprised at how many people will take us home with them! When the business arena (and research question) is more narrow in scope, we may choose research participants based on a screener.