All of knowledge work has this problem. It's hard to objectively judge the quality of someone's work without spending a lot of effort on it. Therefore everyone relies heavily on proxy measures.

You've received a report, a market analysis for the new product you're planning to launch. Reading through it you notice problems: the date on the report doesn't match the date you requested it on, it's from 6 months prior. Several paragraphs have obvious spelling errors. Some graphs are mislabeled and duplicated.