MeasurementResearchSubscription Content Marketing Heads: PR the Toughest ROI Nut to Crack 01/02/2012 By PR News Public relations is the least measurable communications tactic in terms of ROI, according to a survey of U.S. marketers. To continue reading this article, please log in or become a PR News subscriber. PR News Exclusive Content Subscription Required Subscribers: Log In Remember Me Forgot Your Password? New Users: Subscribe This content is accessible to PR News subscribers only. Not a PR News subscriber? Become one today and get access to great content in every issue, plus archives and special reports. Subscribe Now or Go To order by phone or email, please contact the Client Services department at 888-707-5814; firstname.lastname@example.org.