The consumer decides whether or not to buy. Ads can inform and persuade, but they consumer makes the final decision. Advertising reduces competition. Actually, advertising tends to increase competition. As advertising spreads the word and the demand for a product increases, more producers will try to meet consumers'needs.
Advertising can make up for poor product quality and therefore keep a poor product in the market.
Advertising may be able to persuade a consumer to purchase a product one time, but if the consumer is not satisfied, no amount of advertising will encourage additional purchases. Advertising contributes to giving consumers more choices. Since advertising increases competition, more products are sold in the marketplace and consumers have a broaders choice. Advertising is not based on facts about a product. All claims about a product's performance must, by law, be based on facts.