BMJ Open’s first impact factor has been announced: 1.583. We are delighted to have this further evidence that BMJ Open is considered a journal of credible, valued research.
Does a journal’s impact factor matter?
In short – yes. When we surveyed our authors earlier this year, we asked what improvements we could make to BMJ Open. By far the most frequent response was: get an impact factor. The impact factor is over-interpreted, misinterpreted and almost certainly too influential. For as long as it remains important to authors, though, it will remain something journals must promote.
The question of whether a journal’s impact factor should matter, and how much, has been discussed for years. The San Francisco Declaration on Research Assessment (or DORA) highlights some of the issues.
Unlike many journals, BMJ Open doesn’t attempt to select articles on the strength of their likely citation count. So we’ll never have the highest in our field, and you won’t find us worrying about that.
In the future our impact factor may go up or it may go down. Our influence over this will go no further than our continued efforts to ensure BMJ Open publishes thoroughly peer-reviewed open access research and serving all our authors as best we can, so we can build on our reputation as a reliable publishing choice for researchers.
The impact factor is an aggregate measure of BMJ Open’s articles and so says nothing about any individual paper. This is why we also publish article-level metrics. Alongside every paper we publish you can see its abstract, HTML and PDF views, and citations to the article from elsewhere on the HighWire publishing platform.
Such so-called ‘altmetrics’ are increasingly popular. There’s a wealth of information about these available, and the BMJ Web Development Blog is a great place to find out more and keep up to date on these.
It is important to remember that research impact extends well beyond an article’s citation rate. This is especially so in clinical research where impact on public health and clinical care cannot be captured by bibliographic measures.
What is the impact factor?
The impact factor is a journal-level citation metric. It is usually calculated over three years, by adding the number of articles a journal publishes in years 1 and 2, and seeing how often, on average, these articles were cited in year 3. As BMJ Open only has two years’ worth of citation information, our impact factor was calculated using the number of articles we published in 2011 (which Thomson Reuters calculated as 151) and the number of times they were cited in 2012 (239). 239/151 = 1.583
Most-cited from 2011
The following are the papers we published in 2011 with the most citations in the Thomson Reuters Web of Science in 2012:
Armstrong PK, Dowse GK, Effler PV, et al. Epidemiological study of severe febrile reactions in young children in Western Australia caused by a 2010 trivalent inactivated influenza vaccine. BMJ Open 2011;1:e000016. doi:10.1136/bmjopen-2010-000016
da Costa BR, Cevallos M, Altman DG, et al. Uses and misuses of the STROBE statement: bibliographic study. BMJ Open 2011;1:e000048. doi:10.1136/bmjopen-2010-000048
Cohen JI, Yates KF, Duong M, et al. Obesity, orbitofrontal structure and function are associated with food choice: a cross-sectional study. BMJ Open 2011;1:e000175. doi:10.1136/bmjopen-2011-000175
Hotchkiss JW, Davies C, Gray L, et al. Trends in adult cardiovascular disease risk factors and their socio-economic patterning in the Scottish population 1995–2008: cross-sectional surveys. BMJ Open 2011;1:e000176. doi:10.1136/bmjopen-2011-000176