How many of the facts in an average newspaper article are true? A while ago there was a study that compared the amount of factual mistakes in Wikipedia to the amount of factual mistakes in Britannica. Are there similar studies that count the average number of mistakes for mainstream news articles. If a newspaper writes that within a big article that Joe Smith is 42 years old, what's on average the probability that Joe is really 42 years old?

There is a published study called "A Question of Accuracy: How Journalists and Scientists Report Research on Hazards". They state in their conclusion

> Two-fifths of the news stories we coded had one or more statements that were “substantially different” from statements in the original research report

I found another study looking at 14 daily newspapers in the US titled which found the following result

> A survey of 4,800 news sources cited in fourteen newspapers provides a cross-market assessment of newspaper accuracy and the effect of errors on newspaper credibility. Sources found errors in 61% of local news and feature stories, an inaccuracy rate among the highest reported in nearly seventy years of accuracy research.