 And now that we know which types of advertisements influence different ideologies, the question becomes whether they actually make a dent in how people will vote. Green says that they're not really effective, especially when looking at television commercials. I think that the effects tend to be small. Every time they're measured, they're small. I can't think of a single instance where a study was done rigorously and found big effects. Moreover, to the extent that you do find big effects, they tend to subside within a matter of a few days.