Errors in journal articles are common. Most journals now have policies to correct errors in research articles. However, errors in other types of articles often remain uncorrected. I've listed below a few statements in BMJ articles that are either wrong or that are highly unlikely to be true but which remain uncorrected. The BMJ is probably no worse in this respect than other medical journals, but as a member of the BMA, I receive a weekly copy of the print edition and therefore spend more time reading it than other medical journals. This means that I am more likely to pick up errors in the BMJ than in other journals. 

The reported incidence [of polycystic ovary syndrome] varies between 3% and 15% of women of reproductive age. http://www.bmj.com/content/343/bmj.d6407.full

An annual incidence of 15% would imply that after 10 years, a women of childbearing age would have around an 80% risk of developing PCOS. Even the 3% incidence figure would mean that a women of childbearing age would have around a 26% risk of developing PCOS after 10 years. What the author is probably referring to is 'prevalence', which is an entirely different concept to incidence.

Study finds hepatitis C infections more prevalent than previously thought. http://www.bmj.com/content/341/bmj.c4598.full

This news item reported a small pilot study that had a high degree of selection bias in the people who were tested for hepatitis C, thus leading to a much higher rate of hepatitis C infection than reported in the larger surveys carried out by the Health Protection Agency.

In any one year one in four people in the United Kingdom have their thyroid function checked. http://www.bmj.com/content/338/bmj.b725.full.

Two references were given to support this statement. One contained no data on the frequency of thyroid function testing; the other reported that around 10 million thyroid function tests are carried out annually but did not report the source of this statistic. Even if we accept this statistic as accurate, this equates to about one test per six people in the UK, not one per four, assuming that the tests are independent (i.e. each test is carried out on only one patient), which won't be the case. Some people will have multiple tests and hence the actual proportion of the population undergoing thyroid function testing annually will be less than one in six, and very different the authors' quoted figure of one in four.

In 2004 a 1000 point plan called the quality and outcomes framework (QOF) was introduced. http://www.bmj.com/content/341/bmj.c7336.full

In fact, the QOF contained 1050 points when it was introduced in 2004; the number of points was not reduced to 1000 until 2006.

This is just a small selection of errors that I have noticed in the BMJ. As a 'journal of record', should the BMJ not be leading the way in ensuring that any facts it reports are accurate and any mistakes are corrected promptly?