Abstract
Fifteen years ago many editors and academics had never heard of impact factors. Now they are obsessed with them. When I was first editor of the BMJ in 1991 I would attend the editorial boards of our dozen specialist journals—Gut and Thorax, for example—and present data on the journals' impact factors. Usually nobody had heard of impact factors. I explained what they were—and people yawned. Now editors break open bottles of champagne if their impact factor rises by a tenth of a decimal point or burst into tears if it falls. They build their editorial strategies around increasing their impact factors. Authors, meanwhile, can quote the impact factors of the major journals and use them when deciding where to submit their papers. What is this thing called the impact factor? Why does it have such power? And is it a blessing or a curse?