Adults are not the only ones with all-important opinions. Over the years, researchers from different disciplines have used a wide variety of survey methods to assess the views of children and teens.

There are more than 35 million teenagers in the United States, and, according to a recent study, American teens spent almost $80 billion in 2011 alone. Companies that want to gather important market research about how kids think, what they like and what they buy are now creating special online surveys just for this demographic.

While some surveys are for kids as young as 13 — and require parental permission — others have a minimum age requirement of 16. Also, unlike the adult versions, some surveys targeting kids offer discounts and coupons on their favorite products and services as motivation for taking surveys.

Researchers have found that young women in particular are much more likely to share candid opinions and reveal private thoughts through anonymous online surveys and discussion boards than in real-world interviews.

Also, companies that establish partnerships with kids’ online survey sites are privy to valuable information about the types of products this generation is most likely to buy, even three or four years down the road.