Conventional methods of model construction and testing are not well suited to the features of large longitudinal survey data sets. Conventional methods assume (1) equal time intervals between observations, (2) simultaneous observations, and (3) that missing observations are rare. As a result,...

The One Parameter Inequality Process (OPIP) long predates the Saved Wealth Model (SWM) to which it is isomorphic up to the different choice of stochastic driver of wealth exchange. Both are stochastic interacting particle systems intended to model wealth and income distribution. The OPIP and...