62% of the more than 18,000 U.S. consumers it polled said social media had no influence on their buying decisions
sure, there are of course individual ad campaigns that fails, but this isn't how you come to that understanding.
while i'm not a professional "pollist", this seems tremendously flawed. first, advertising's effects are largely on the subconscious. it's not like you see an add for mcdonald's and think out loud to your self "i'm going to get some mcdonalds". it's more like you see 500 ads for mcdonalds where multicultural hipsters are hanging out and having fun eating mcdonalds on youtube and the next time you are driving through a pack of fast food restaurants, your familiarity with mcdonalds makes you lean one way. it's why restaurants like mcdonalds, burger king, taco bell, applebees, dennys, and so on make so much $. it's not because they are good, it's because people are familiar with them (usually combined with them not being terrible).
second, people like to think they are individuals with free will. if you ask them if they are driven to purchase goods and services by ads, of course they are going to say no.
advertising WORKS. you can see this by the fact that companies continue to up their spending, hundreds of billions year after year. if there's one thing i do know, it's that corporations like money. they wouldn't continue to shell out greater and greater sums every year if they weren't measuring positive results.