You may find this lit review of interest https://www.tandfonline.com/doi/epdf/10.1080/00913367.2017.1339368?src=getftr&utm_source=wiley&getft_integrator=wiley
Something to keep in mind is that we can’t really compare with the past, because things like magazines, TV, newspapers and their audiences are not what they were before. So an auto dealer that used to advertise heavily in the Sunday paper needs to try something different.