You know it’s news when it becomes a trending topic on Twitter.

A new Nielsen-SocialGuide study shows that the social network can be valuable in increasing TV ratings, at least among the coveted 18-34 year old demographic. The study found that a 1% increase in ratings for both premiere episodes and for midseason episodes corresponds to an 8.5% and a 4.2% increase in Twitter volume, respectively.  According to SocialGuide, 32 million people in the U.S. tweeted about TV in 2012, and networks and advertisers are paying attention.

By analyzing tweets about live TV, the study confirmed the relationship between the social network and ratings, identifying Twitter as one of three “statistically significant variables” (in addition to prior-year rating and advertising spend) which align with TV ratings.

“While prior-year rating accounts for the lion’s share of the variability in TV ratings, Twitter’s presence as a top three influencer tells us that tweeting about live TV may affect program engagement,” according to Andrew Somosi, CEO of the Nielsen-owned SocialGuide. “We expected to see a correlation between Twitter and TV ratings, but this study quantifies the strength of that relationship.”

Nielsen pointed to the rise in media consumption across multiple device screens as a reason for the correlation. “We know that 80% of U.S. tablet and smartphone owners who watch TV use their device while watching at least several times a month. WE also know that 40% of U.S. tablet and smartphone users visit a social network while watching TV.”

Among the slightly older set of 35-49 year olds, a 14% increase in Twitter volume corresponds to a 1% increase in TV program ratings, reflecting a stronger relationship between Twitter and younger audiences.

Further, the study found the correlation strengthens for midseason episodes for both age groups. An increase in Twitter volume of 4.2% and 8.4% is associated with a 1% increase in ratings for 18-34 year olds and 35-49 year olds, respectively. By midseason, Twitter was responsible for more of the variance in ratings for 18-34 year olds than advertising spend.

“The TV industry is dynamic and it was important for us to analyze multiple variables to truly understand Twitter’s impact on TV ratings,” said Mike Hess, EVP of media analytics for Nielsen. “While our study doesn’t prove causality, the correlation we uncovered is significant and we will continue our research to deepen the industry’s understanding of this relationship.”