Source: Mercatus Center
Latest Data: https://www.quantgov.org/regcensus-explorer

The Mercatus Center's State RegData project collected and analyzed the regulations of 46 states plus the District of Columbia between June 2015 and August 2019.  The regulatory codes of Arkansas, Hawaii, New Jersey, and Vermont could not be analyzed due to data limitations. The numbers represent the number of regulatory restrictions by state.

Researchers used "text analysis and machine learning algorithms to quantify how many words and regulatory restrictions each state’s regulations contain as well as to estimate which sectors and industries of the economy those regulations are likely to affect. As in all RegData datasets, regulatory restrictions are a metric designed to act as a proxy for the number of prohibitions and obligations contained in regulatory text, as indicated by the number of occurrences of the words and phrases “shall,” “must,” “may not,” “required,” and “prohibited” in each state’s regulations."  These estimates are only for state-level regulations.

Since 2017 the data has been released one-by-one as each state analysis was completed. The year 2019 reflects the latest report publication year. For more information about the data and when it was produced please see https://www.mercatus.org/publications/regulation/quantifying-regulation-us-states.

RegData is a sub-project of QuantGov. It is the specific process of using the QuantGov platform to collect, quantify, and analyze regulatory code.