In 2016, an average influencer marketing programme campaign cost marketers between £20,000 and £40,000. The expenditure was expected to double this year.But, for marketers, proving ROI on influencer marketing is one of the biggest challenges by brands and influencers alike.Econsultancy’s James Collins has published an article on using sales to measure influencer marketing ROI. The article focuses on raising awareness and reaching new customers, engagement, sales and conversions etc.On measuring engagement, Collins says, “Web traffic in general – whether that’s from new or... [...]