Using a sample of 200,000 comScore panelists in conjunction with data from supermarket loyalty programs, the two companies compared the purchasing behavior of users exposed to online CPG ads against those who did not see the ads.

Over the course of a three-month period, the study found that online ad campaigns featuring static ads and rich media units boosted supermarket sales of the advertised goods by an average of 9 percent.

The firms claim this compares to an average lift of 8 percent for TV advertising, across a 12 month period, citing research by Information Resources.

In addition, around 80 percent of the online ad campaigns analyzed resulted in "statistically significant" sales increases for the advertised brands, the pair said.

Though the specific campaigns and brands being monitored were not disclosed, they included a range of product categories, such as cereal, cookie mixes, pizza, juice drinks, snack bars, pasta, tea, deodorants, and toothpaste. DunnhumbyUSA clients include brands such as Coca-Cola, General Mills, Kimberly-Clark, PepsiCo, and Procter & Gamble.