“Measuring or defining return on investment” was the top challenge when it comes to social media, according to a survey of marketing executives by The Creative Group, the marketing/creative staffing division of Robert Half International Inc. (NYSE: RHI).

Forty percent of marketing executives cited “measuring or defining return on investment” as the biggest stumbling block when it comes to social media. “Finding knowledgeable staff to executive social media tasks,” ranked as the second-most cited hurdle. It was reported as the biggest challenge by 19 percent of marketing executives.

“The social media landscape is changing constantly, making it difficult for companies to not only determine which channels to focus on but also how to effectively measure the impact of their efforts,” said Donna Farrugia, executive director of The Creative Group.

The survey included 500 marketing and advertising executives.