However, accounting identities can be used in theoretical interpretation to arrive at causal explanation, but this requires examining relevant behaviors. For example, one entity's expenditure is a flow that increases another entity's income, which will have a cumulative influence on a stock.
Stock-flow analysis observes stock-flow consistency. Accounting identities are boundary conditions of stock-flow consistency.
It’s fairly common for economists to confuse accounting identities and behavioural relationships.
Question: What is the best way to find it?
Answer: The behaviour of output (at home and abroad) is not discussed in their analysis.
It’s not always the case that it’s true but a good way to find – check whether the economist is talking of the effect of changes in stocks or flows on output.
It’s also of course important to discern what someone is literally saying and what that person is trying to say. Economists aren’t the best communicators.…The Case for Concerted Action
Output At Home And Abroad