<div dir="ltr"><a href="http://www.nature.com/neuro/journal/v6/n8/full/nn0803-783.html" target="_blank" style="font-family:arial,sans-serif;font-size:12.800000190734863px">http://www.nature.com/neuro/journal/v6/n8/full/nn0803-783.html</a><br style="font-family:arial,sans-serif;font-size:12.800000190734863px">
<div style="font-family:arial,sans-serif;font-size:12.800000190734863px"><br></div><div style="font-family:arial,sans-serif;font-size:12.800000190734863px"><a href="http://www.nature.com/neuro/journal/v6/n8/fig_tab/nn0803-783_F1.html" target="_blank">http://www.nature.com/neuro/journal/v6/n8/fig_tab/nn0803-783_F1.html</a><br>
</div><div style="font-family:arial,sans-serif;font-size:12.800000190734863px"><br></div><div style="font-family:arial,sans-serif;font-size:12.800000190734863px"><br></div><div style="font-family:arial,sans-serif"><quote></div>
<div style="font-family:arial,sans-serif"><br></div><div style="font-family:arial,sans-serif"><span style="font-family:Verdana,Arial,Helvetica,sans-serif">The most obvious feature of these distributions is that they are highly skewed (</span><a href="http://www.nature.com/neuro/journal/v6/n8/full/nn0803-783.html#f1" target="_blank" style="color:rgb(3,125,125);font-family:Verdana,Arial,Helvetica,sans-serif">Fig. 1</a><span style="font-family:Verdana,Arial,Helvetica,sans-serif">); in every case, the medians are lower than the means, reinforcing the point that a journal's IF (an arithmetic mean) is almost useless as a predictor of the likely citations to any particular paper in that journal</span><sup style="font-family:Verdana,Arial,Helvetica,sans-serif"><a href="http://www.nature.com/neuro/journal/v6/n8/full/nn0803-783.html#B2" target="_blank" style="color:rgb(3,125,125)">2</a></sup><span style="font-family:Verdana,Arial,Helvetica,sans-serif">.</span><br>
</div><div style="font-family:arial,sans-serif"><span style="font-family:Verdana,Arial,Helvetica,sans-serif"><br></span></div><div style="font-family:arial,sans-serif"><span style="font-family:Verdana,Arial,Helvetica,sans-serif">...</span></div>
<div style="font-family:arial,sans-serif"><span style="font-family:Verdana,Arial,Helvetica,sans-serif"><br></span></div><div style="font-family:arial,sans-serif"><span style="font-family:Verdana,Arial,Helvetica,sans-serif">What is most distinctive about the higher-impact journals is their long tails, corresponding to a relatively small number of papers that are exceptionally highly cited, and which therefore contribute disproportionately to the IF and, presumably, to the overall prestige of those journals. At the other end of the distribution, the lower-impact journals tend to publish more papers with few citations.</span><span style="font-family:Verdana,Arial,Helvetica,sans-serif"><br>
</span></div><div style="font-family:arial,sans-serif"><span style="font-family:Verdana,Arial,Helvetica,sans-serif"><br></span></div><div style="font-family:arial,sans-serif"><span style="font-family:Verdana,Arial,Helvetica,sans-serif">...</span></div>
<div style="font-family:arial,sans-serif"><span style="font-family:Verdana,Arial,Helvetica,sans-serif"><br></span></div><div style="font-family:arial,sans-serif"><span style="font-family:Verdana,Arial,Helvetica,sans-serif">Properly interpreted, citation data can be a valuable tool for evaluating journals, papers, authors and perhaps even editors. But it is a blunt instrument at best, and when complex distributions are reduced to simple averages, then much of the usefulness is lost. Journal impact factors cannot be used to quantify the importance of individual papers or the credit due to their authors, and one of the minor mysteries of our time is why so many scientifically sophisticated people give so much credence to a procedure that is so obviously flawed.</span><span style="font-family:Verdana,Arial,Helvetica,sans-serif"><br>
</span></div><div style="font-family:arial,sans-serif"><span style="font-family:Verdana,Arial,Helvetica,sans-serif"><br></span></div><div style="font-family:arial,sans-serif"><span style="font-family:Verdana,Arial,Helvetica,sans-serif"></quote></span></div>
</div>