1. A non-transitory computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for determining a complexity of a transaction between a first entity and a second entity, wherein the first entity interacts with the second entity, and wherein the second entity is a human, comprising: determining a first probability of success for a first portion of the transaction which is associated with actions of the first entity; determining a second probability of success for a second portion of the transaction which is associated with actions of the second entity; calculating a transactional complexity for the transaction based on the first probability of success and the second probability of success, wherein calculating the transactional complexity involves calculating the natural log of the inverse of the product of the first probability of success and the second probability of success; and calculating an inter-complexity for a set of transactions by calculating a sum of probability-weighted transactional complexities for each transaction.