Earned media, the goal of any PR campaign, is a highly effective way for a brand to generate awareness in a social network – but cannot be guaranteed. Meanwhile, social ads (a form of network endorsement on ads) drive engagement and reach similar to traditional paid-for campaigns.

These are the key finding of a study called Advertising Effectiveness by Nielsen’s Jon Gibs and Facebook’s Sean Bruich.

Facebook has developed a series of ad executions that are a hybrid between earned and paid media, incorporating social elements. These are served in a social context, referencing the names of user’s friends that are fans of the brand, or appear in the news feed of users that have engaged with the advertiser.

Nielsen conducted six-months of research consisting of surveys of more than 800,000 Facebook users and more than 125 individual Facebook ad campaigns from 70 brand advertisers.

The report includes analysis of ad-led campaigns.  It says that ads provide a predictable means of reaching a large targeted demographic, whereas earned media is neither predictable, nor able to deliver a comparable reach.

“[…] Today a media outlet broadcasting a brand is not the only form of earned distribution. The consumer is now invited to broadcast, and hopefully endorse, the brand to their online friend. As a result, brands are turning to the tools and advertising opportunities provided by social media outlets, such as the organic impressions used by Facebook.”

Where Facebook ads incorporate a social component, Nielsen found that the endorsement of a network led to recall increasing from 10 to 16 per cent, awareness doubling from 4 to 8 per cent, and purchase intent rising from 2 to 8 per cent.

The results are compelling but the one flaw in the study is its emphasis on social ad campaigns. It omits an analysis of the impact of standalone earned media campaigns on Facebook, what we’d more commonly recognise as traditional PR or word of mouth campaigns.

The report concludes that further work needs to be done to understand the relationship between engagement in a social network and long-term brand value & offline sales.

Stephen Waddington (@wadds) is the managing director of multi-sector PR agency Speed.