Since 2010, the Center for Plain Language annually judges the quality of content produced by US government agencies. The results for 2017 are shown below.
I love these report cards for several reasons but chief among them is that they use an evidence-based approach. On a shoestring budget. Most complaints about content quality are vague. But the Center describes the methods used to evaluate quality. You can read the details in their white paper.
In the past, I’ve used their white papers to introduce the field of technical communication to college students. I encourage others to do the same. Thanks to the volunteers at the Center, who share their work with the world and keep our public servants accountable.