Interesting bit about their technique:<p>"Could regulation be increasing barriers to entry, raising the costs of reallocation, and slowing the diffusion of productivity innovations? To test the hypothesis that regulation is reducing dynamism Nathan Goldschlag and I combined data on dynamism with an industry level measure of regulation. Our measure of regulation is produced by an innovative technique that combs the Code of Federal Regulations (CFR) for restrictive terms or phrases such as “shall,” “must,” “may not,” “prohibited,” and “required”. The count of restrictive words in each section is then associated to industries via a machine learning algorithm that recognizes similarities between the language in that CFR section and industry language (e.g. a section of the text with words such as “pipeline” would be associated with the oil and gas industry). In this way, we can associate each industry with an index of regulation derived from the entire CFR."