Liveliness is defined as the ratio of the sum of Coin Days Destroyed and the sum of all coin days ever created. Liveliness increases as long term holder liquidate positions and decreases while they accumulate to HODL. This metric was created by Tamas Blummer. For a detailed commentary see this post.

This is the Point-in-Time (PiT) variant of Liveliness. PiT metrics are strictly append-only and their history is immutable. The historic data does not necessarily reflect the best current knowledge, but the information at the time when a data point was first computed. PiT metrics are ideal candidates for applications in model backtesting and related quantitative purposes. Read our article on PiT metrics for more information.