There’s a new twist in the long-running debate on the virtues and vices of reach and targeting: an academic study argues that brands reduce the impact of their marketing with overly-broad reach.

Redefining reach

The study, by Twitter and the University of Oxford’s Saïd Business School, defines reach as a percentage of the ‘breadth’ of audience that the brand wishes to communicate with.

Top-line findings

• Campaigns on Twitter pursuing the broadest-possible reach consistently delivered a brand lift of around 2%.
• In contrast, the more targeted a campaign, the greater variance of results – from stellar performers to campaigns that actually...