The thousands of YouTube Partner channels have made sitting through pre-roll ads less of a nuisance and more of an understanding: you serve us the ad, we watch five seconds of it, and then we go on to our camel videos. Of course, this is occasionally impossible, as some channels require users to sit through an entire pre-roll ad before viewing their video. It’s a bit of a nuisance for viewers, but does it show a tangible gain for advertisers?

A recently study from TubeMogul says yes. The analytics company has determined that sitting through an entire ad (as opposed to a skipped or interrupted one) increases the degree to which a viewer associates a campaign with a brand. Simply viewing an ad made a viewer 8.3% more likely to make the association (compared to not viewing any ads), but staying with the ad to its conclusion bumped that percentage up to 20.5%. The difference can be seen in these slick graphs, all courtesy of TubeMogul:

Sure enough, viewers are completing their ads. For a 15-second pre-roll, more than three quarters of all viewers watch the entire ad, whether they’re forced to or not. Maybe that stat will discourage advertisers from simply plugging one of their videos into an ad campaign to boost its view count.

Of course, in the end, it’s most important to remember the biggest strength of pre-roll ads: there are a ton of openings for them. The YouTube audience is currently viewing over 331 million pre-roll  ads each day, larger than the entire population of the US. Given the amount of time I spend on YouTube, I probably watch about 100 million of ‘em.