Not sure how many local Jack FM's Cumulus owns these days, but Jack is one of the most locally focused and researched concepts around today. Each Jack that SparkNet consults is tailored specifically for its local market. Obviously, the satellite version of it can't be done that way, but it's still well-researched.
When I worked for Cumulus, it did a ton of market research. It spent more on research in its first three months in my local market than any other company had spent the previous 15 years combined. Having said that, most of the research money it spent was for marketing research. It was research done to increase sales, and programming research was limited to what holes the market had and whether we had the right parts in place to fill any of them without compromising our existing revenue. I left after about four months, and that cluster had one format change of a station from classic rock to oldies shortly afterward. The company also did more music research than we'd ever done previously, but that research, far as I know, wasn't done completely locally. Cumulus playlists had a reputation for being vanilla for a reason. Adds and moves were generally done from Atlanta, and local markets had little control over that. The growth strategy Cumulus employed in its early days was to buy bottom feeders and move them to the middle of the pack. It was fine with plateauing somewhere in the middle so long as it did well enough to get national ad buys. I understand centralized playlists are a thing of the past at Cumulus today, but I don't know exactly what system it's using now. I know it still has brand managers and has contracts with consulting firms, but I don't know how much freedom local markets have to work with each or if they can work with outside firms. I can't imagine most smaller Cumulus markets have the budget to go outside of the company, but it might happen in larger ones.