I was recently working on a book idea (does human knowledge double every 5 years?) and as part of this I calculated the compound annual growth rate of academic journal publications and patent activity in a number of fields to see if the formal output of human knowledge did in fact double every five years. I did the research using a weblog–if you want to see what I was doing, it’s here.

My question to you is, would a similar measurement of what we are looking at here and on the wiki be useful in assessing the timeline for impact? I fear it would (fear because it takes a lot of time). If you agree, tell me in the comments and I will do it. If you think that past performance has no relevance to future behaviour, I need to hear that, too.

Here is the league table for the sectors I measured during my research (I apologise for the formatting):

As shown, only 10 of the 25 grow faster than 14.87% per year, which is what is needed to double every 5 years.

Field : CAGR% : Doubling Period (Yrs)

1. Nanotechnology patents : 44.91% : 1.87
2. Nanotechnology journals : 42.03% : 1.98
3. Global warming patents : 38.62% : 2.12
4. Prions patents : 33.76% : 2.38
5. Programming patents : 33.53% : 2.4
6. Stem Cells patents : 26.47% : 2.95
7. Prions journals : 25.57% : 3.04
8. Global warming journals : 24.71% : 3.14
9. Epidemiology patents : 17.37% : 4.33
10. Stem Cells journals : 16.63% : 4.51
5 Year Doubling Rate : 14.87% : 5
11. Programming journals : 12.55% : 5.86
12. Alzheimers Disease patents : 11.26% : 6.5
13. Oncology patents : 10.02% : 7.26
14. Alzheimers Disease journals : 9.65% : 7.52
15. Oncology journals : 9.23% : 7.85
16. DeSolla Price estimate of world literature growth : 7.0% : 10.24
17. Epidemiology journals : 6.22% : 11.49
18. Mars journals : 5.78% : 12.34
19. Shale oil journals : 5.53% : 12.88
20. US patent grants : 5.21% : 13.65
21. University enrollment worldwide : 4.85% : 14.64
22. Publications in astrophysics since 1970 4.0% 17.67
23. US patent applications 3.88% 18.21
24. U.S. Book publishing 3.65% 19.33
25. Shale oil patents 2.58% 27.21

Remembering that I tried to focus on areas where I expected to see robust growth, the fact that only 40% of the sectors I surveyed showed adequate growth to double human knowledge in 5 years is not good news.