Adler-Weiner Research is a focus group company that has locations in Chicago, Los Angeles, and Orange County. The Chicago branch is located in Lincolnwood and has a parking lot (a big plus!). I have done several studies with them and have found that they are very easy to work with, polite, call regularly, and always pay in cash. The focus group I completed this last week also included sandwiches, as it was scheduled in the evening.
Most invitations are sent by email, but I’ve also received invitations by phone. As always, check that your home or work zip code area in the pool area before applying (Chicago here and here; Los Angeles here; Orange County here).
For information on other market research companies to sign up with, check the posts here.