There's a widespread perception among scientists that we're living in an era of relentless growth in terms of the number of scientific papers being published.
Many say that quantity has increased at the expense of quality: people are publishing "any old rubbish" or splitting their work into as many papers as possible, driven by the publish-or-perish culture of modern academia.
But is this true? To try and find out, I looked at the number of papers published each year, in English, on PubMed, for the past 30 years.
Here's the data: it shows an increase in the number of papers coming out each year, except for a small negative blip around the year 1997:
Now, when I first eyeballed this curve, I got the impression that growth has accelerated recently, consistent with the "recent pressure to publish" idea.
But here's the same data with each year's publications expressed as a ratio to the previous year's:
This reveals that the relative annual growth in the number of papers published has actually been pretty constant over the past 30 years. It's generally been around 4% (ratio of 1.04), and almost always within the range 2% to 6%. In other words, every year, scientists publish the same number of papers they did last year, plus about 4%.
The past few years have not seen especially strong growth, relatively speaking. At most we can say that year-on-year growth has been at the upper end of the historical range, 4 to 6%, but that's no faster than in the 1980s.
Still, this is a lot of growth. Assuming that it stays at 5% year on year, we'd expect a million new papers published in 2016, and two million in 2030.
But is that really feasible? Is there any good reason that science should grow exponentially in this way? Can that continue, or will we reach "peak science" or at least a plateau?