Ecommerce retailers need to find ways to improve the performance of their web sites, particularly when viewed on mobile devices, according to a new research report, “2018 eCommerce Website Performance.”

The research, conducted by Retail Systems Research, tested 80 top retail sites for the speed at which each desktop and mobile site laded, evaluated the ease with which a shopper could find a product, and noted what tools, such as product reviews or chat features, were provided. The retailers were than ranked from 1 to 80 based on the data.

Key findings:

Retailers did not do well on the evaluation. The average score was 45 percent and the highest only 63 percent. These scores mean the needle  is moving in exacty the wrong direction, the report says. It identifies third party features that are not tested for their affect on site performance as the culprit.

Mobile performance is “embarrassingly slow.” While many retailers received high marks for beautiful, intuitive and shoppable mobile experiences, almost all were penalized for very slow mobile performance.

Rich Stendardo, CEO of Yottaa, which published the report, said, “This year’s RSR report highlight the importance of third-party technologies and the impact they have on site performance. These technologies, such as personalization and live chat provide great online experiences to shoppers, but they also risk slowing down page load speeds, which causes shoppers to leave a site.”