NEW YORK: Frito-Lay, Harley-Davidson and CVS are among the brands which have most effectively engaged female consumers in the US during the last year, a study has found.

Women at NBCU, a division of NBCUniversal, used search data from Compete, social media statistics from New Media Strategies and in-person word of mouth analysis by the Keller Fay Group to build an index ranking 500 advertisers on this metric over 12 months.

Frito-Lay set a new record for generating the most "likes" on Facebook in 24 hours, adding 1.5m fans of both genders, partly thanks to creating a branded farm on FarmVille so players could make healthy "virtual goods".

It also live streamed a Flavour Kitchen event in Times Square, providing cooking demonstrations and tips for busy mums, on its Facebook page, rising 159 places in the charts as a result.

Harley-Davidson entered the index in 194th position after rolling out a dedicated website for female enthusiasts and holding offline events, like a "biker boot camp" and "women riders month", for the same audience.

CVS, the pharmacy chain, enjoyed the longest period of "steady buzz", rising in the index for eight months in a row and peaking in 27th, with a photography contest conceived with the WWF proving especially popular.

Similarly, its new "Beauty Board", made up of expert commentators, offered guidance about all issues related to beauty and fashion on Facebook.

Kotex, owned by Kimberly-Clark, was praised for exploiting "controversial buzz", leaping 130 places in the rankings by breaking category conventions when promoting U by Kotex Tween.

The campaign for this product, aimed at 8- to 12-year-old girls, sought to start a conversation between mothers and daughters, using a special online forum for parents and their children to talk confidently and openly.

Elsewhere, Mattel was lauded for securing the "best viral buzz" for a digital campaign, employing Facebook, Foursquare, Twitter and YouTube to ask consumers if Barbie, the doll, should reunite with her "boyfriend", Ken.

Alongside such efforts, it launched an internet reality series to find a real-life "Ken", and ran outdoor ads to drive interest among web users, ultimately seeing Barbie ascend rapidly to 74th position in the Women at NBCU index.

Melissa Lavigne-Delville, a vice president at NBCUniversal, said: "The most successful brands we've seen over the last 12 months not only engaged women across multiple platforms, but also created the opportunity for women to engage with one another and contribute to the brand conversation."

Data sourced from NBCUniversal; additional content by Warc staff