The survey, sponsored by the Word of Mouth Marketing Association (Womma) and the American Marketing Association, found that while spending on social media and offline WOM campaigns is likely to rise at a health clip, a large majority of marketers cite measurement as an obstacle.

Womma chairman-elect Brad Fay, co-founder of the WOM measurement firm Keller Fay, said: “This is the great challenge for our industry: to provide more tools to show the return on investment from word-of-mouth marketing.”

The survey of 328 marketing executives found that 70% of participants were expecting to increase their spending on social media in 2014, compared to 59% for digital advertising and 53% for email marketing. Meanwhile, 29% are planning for an increase in offline WOM spending, versus 16% for print, 14% for product sampling and 9% for TV.

However, 89% of participants said they still experience difficulty in measuring offline WOM, 85% in showing a return on investment, and 79% in measuring social media.

“WOM is such an important aspect of marketing today, because it is where meaningful conversations happen with customers” added Nancy Costopulos, chief marketing officer at the American Marketing Association. “This study is a call to action for our industry to help marketers prove the business value of WOM.”