Are macro-economic models a waste of time? Especially the ones that involve mathematic models?

Question

At uni I had quite a few economics courses and my conclusion was that most of macro-economic models are worthless, and a laissez faire system is better, because the government doesn't have to worry much about economic issues because it has little impact on them.
I say this because of the ceteris paribus assumptions in many of them, which is utopic, and also because there's still discussion about why many important economic events happened in the past without a conclusive explanation; also forecasting with certainty human behaviour and its outcome even through mathematic formulas to me is nonsense.

Answer 1

No.

First, laissez faire is a macroeconomic model!

Second, macroeconomic models taught at the undergraduate level are qualitatively different than the models taught at the graduate level. At the undergraduate level, you are trying to provide a basic understanding of the forces at work. You would not expect a person with an undergraduate degree to be able to model prospective near term unemployment in Florida.

Third, it is generally accepted by economists that governments can have little positive impact on the economy except in times of crisis.

Finally, the test of a model is "does it do what it is intended to do?" If the answer is "yes," then you keep the model. If the answer is "no," then you get a new model.

One last note on assumptions, assumptions only matter if they trigger model error. Otherwise, the simplifications used in assumptions are required to permit modeling to occur at all. We have, after all, the perfect model of the world. Just look outside your window and you will see it.