The study, from IPG Media Lab, Integral Ad Science and Cadreon, involved nearly 10,000 participants and 189 different ad scenarios and was intended to quantify the relationship between viewability and brand metrics. 

Results showed that ads that simply met the Media Rating Council’s (MRC) viewability standard did not have a measurable impact on recall (though exceeding them did have a significant effect). More specifically, it was shown that while some ads ( 6%) falling below that standard could have an impact on ad recall, some ads ( 16%) above the standard don't have an impact.

Nevertheless, it was found that overall, viewability was highly related to ad effectiveness: ad recall by time in view rose from 1% at under MRC standard, to 3% at MRC standard (which varies by ad type) to 8% at four second exposure and 17% at seven second exposure. In terms of percentage in view, recall was at 5% at under standard viewability, 4% at MRC standard, 9% at 75% viewability and 11% at 100% viewability.

The full report can be found here.