Are you talking about call-out research? I don't think many stations or groups do much of that anymore. In fact, the bottom fell out of any call out research with the proliferation of smart phones. Most consumers don't use their phones to make or answer calls anymore, and many have shed having land lines.
"Call out" is a generic term for a kind of research that generally is focused on currents. A person is recruited, generally replicating methods used by Nielsen (the idea is to capture people who would also be PPM panelists or diary keeper) and they are asked to go online and take a short music and perceptual test. In some cases, the test itself is done over the phone. Either way is workable, and the key is finding actual station and format listeners who listen enough to know the good songs from the bad ones.
If the test is for currents, they will hear 20 to 30 snippets or hooks and score each one with a number or by sliding a scale. As soon as they score one, they get the snippet of the next.
If the test is for library, they likely will be offered a nice compensation such as a gift card. Then they will do a test of more songs, often breakable into multiple sessions of a couple of hundred songs each. Again, online using some kind of a scale of "hate it" to "love it". Also a place to click "unfamiliar" and, sometimes, "used to like but tired of it".
This test of hundreds of songs is still called an AMT, or auditorium music test even though we quit using auditoriums about 40 years ago and moved to hotel meeting rooms and now, to online testing.
The recruiting is generally done by a professional recruiter for the AMT, as there needs to be assurance that the person taking the test is the person who was recruited and, also, that they are the "right" people for the station's format in age, gender and station usage.