What is the tourism marginal effect prediction model?

Testing of parallel trends and dynamic effects. Parallel trends and dynamic effect testing are tourism marginal effect prediction models. Marginal effects break the original thinking, that is, the usual "input-output" model. When you're somewhere on the "margin," this model breaks down. Since it is called "marginal effect", it means that it summarizes some phenomena in life, not just in the field of economics. Marginal effect, sometimes also called marginal contribution, refers to the gradual decrease in unit utility brought by consumers when they gradually increase one unit of consumer goods.