There are a lot of scientific papers out there. One estimate puts the count at 1.8 million articles published each year, in about 28,000 journals. Who actually reads those papers? According to one 2007 study, not many people: half of academic papers are read only by their authors and journal editors, the study's authors write.

But not all academics accept that they have an audience of three. There's a heated dispute around academic readership and citation—enough that there have been studies about reading studies going back for more than two decades.

In the 2007 study, the authors introduce their topic by noting that “as many as 50% of papers are never read by anyone other than their authors, referees and journal editors.” They also claim that 90 percent of papers published are never cited. Some academics are unsurprised by these numbers. “I distinctly remember focusing not so much on the hyper-specific nature of these research topics, but how it must feel as an academic to spend so much time on a topic so far on the periphery of human interest,” writes Aaron Gordon at Pacific Standard. “Academia’s incentive structure is such that it’s better to publish something than nothing,” he explains, even if that something is only read by you and your reviewers.

But not everybody agrees these numbers are fair. The claim that half of papers are never cited comes first from a paper from 1990. “Statistics compiled by the Philadelphia-based Institute for Scientific Information (ISI)indicate that 55% of the papers published between 1981 and 1985 in journals indexed by the institute received no citations at all in the 5 years after they were published,” David P. Hamilton wrote in Science.

In 2008, a team found that the problem is likely getting worse. “As more journal issues came online, the articles referenced tended to be more recent, fewer journals and articles were cited, and more of those citations were to fewer journals and articles.” But some researchers took issue with that study, arguing that using different methods you could get quite different results. “Our own extensive investigations on this phenomenon… show that Evans’ suggestions that researchers tend to concentrate on more recent and more cited papers does not hold at the aggregate level in the biomedical sciences, the natural sciences and engineering, or the social sciences,” the authors write. This group of researchers found that plenty of old papers, for instance, were racking up readers over time.

It seems like this should be an easy question to answer: all you have to do is count the number of citations each paper has. But it’s harder than you might think. There are entire papers themselves dedicated to figuring out how to do this efficiently and accurately. The point of the 2007 paper wasn’t to assert that 50 percent of studies are unread. It was actually about citation analysis and the ways that the internet is letting academics see more accurately who is reading and citing their papers. “Since the turn of the century, dozens of databases such as Scopus and Google Scholar have appeared, which allow the citation patterns of academic papers to be studied with unprecedented speed and ease,” the paper's authors wrote.

Hopefully, someone will figure out how to answer this question definitively, so academics can start arguing about something else.