Here is the actual statement about 2%: http://schd.ws/hosted_files/buildstuff2013/ce/The%20unreasonable%20effectiveness%20of%20dynamic%20typing%20for%20practic

Here is the actual statement about 2%: http://schd.ws/hosted_files/buildstuff2013/ce/The%20unreasonable%20effectiveness%20of%20dynamic%20typing%20for%20practical%20programs.pdf http://schd.ws/hosted_files/buildstuff2013/ce/The%20unreason... "2% of reported Github issues for Javascript, Clojure, Python, Ruby, are type errors" The study referenced in that presentation, http://www.inf.fu-berlin.de/inst/ag-se/teaching/V-EMPIR-2014/doc/jccpprtTR.pdf http://www.inf.fu-berlin.de/inst/ag-se/teaching/V-EMPIR-2014..., study 80 implementations of the same program by 74 people. The reported times in the study do not last for over 63 hours. The study referenced in the blog post, http://courses.cs.washington.edu/courses/cse590n/10au/hanenberg-oopsla2010.pdf http://courses.cs.washington.edu/courses/cse590n/10au/hanenb..., study "49 subjects that studies the impact of a static type system for the development of a parser over 27 hours working time." The only conclusion that can be drawn from these datapoints, if 2 is enough, is that programs written in no longer than 3 days time can be implemented faster in dynamic languages than statically typed languages. There's nothing that calls out maintainability of a program over years of time, nor the number of pre-written libraries used in those programs recorded.