A survey of senior ad buyers worldwide reveals a range of issues many have when it comes to programmatic advertising.

According to December 2017 data from B2B market research company London Research—in partnership with Truth, a media agency—nearly half of respondents said the lack of consistent measurement and metrics was one of many concerns they had about programmatic advertising.

Lack of agency transparency and the absence of visibility on third parties rounded out the top three concerns mentioned.

Meanwhile, ad fraud was another trepidation many had—some 37% of senior ad buyers were worried about it. And nearly as many cited ad viewability.

But while programmatic advertising may come with concerns, it also delivers many benefits. The same study found that a majority of senior ad buyers were able to target and optimize campaigns effectively, as well as scale them, because of programmatic advertising.

More than four in 10 respondents said they got better return on ad spend, and almost as many reported reduced costs.

eMarketer estimates 83.6% of US digital display ad dollars will transact programmatically by 2019.