New research shows unnamed sourcing lowers credibility for readers:

“Readers sometimes believe sources have a vested interest in being anonymous, and they may also interpret the use of un-named sources as reporter incompetence, according to the study. Either way, the result is lower credibility.

The researchers, Miglena Sternadori and Esther Thorson, examined how readers reacted to investigative news stories using anonymous sources, as well as how the designation of a story as an “award winner” affected believability.

Stories in which the source had a vested interest and stories in which the author did not explain the use of anonymous sources ranked lowest in terms of credibility. Stories in the “award winners” category had more credibility with readers.

Interesting because some earlier research wasn’t as conclusive.