These graphs represent the historical decentralisation of software development for various blockchain implementations. Each metric value is calculated based on the distribution of some contribution type (e.g. number of commits or lines changed) across contributors over a sample of commits. Read more...

Shannon entropy (also known as information entropy) represents the expected amount of information in a distribution. Typically, a higher value of entropy indicates higher decentralization (lower predictability).

The Herfindahl-Hirschman Index (HHI) is a measure of market concentration. It is defined as the sum of the squares of the market shares (as whole numbers, e.g. 40 for 40%) of the entities in the system. Values close to 0 indicate low concentration (many entities are responsible for a similar number of contributions) and values close to 10,000 indicate high concentration (one entity responsible for most or all contributions).

The Theil index captures the lack of diversity, or the redundancy, in a population. In practice, it is calculated as the maximum possible entropy minus the observed entropy. Values close to 0 indicate equality and values towards infinity indicate inequality.

The 1-concentration ratio represents the share of contributions that are made by the most “powerful” entity, i.e. the entity that is responsible for the highest number of contributions.

The total entities metric captures the number of contributors that made at least one contribution in some sample window.