The document discusses economic growth models including the Harrod-Domar growth model. It presents the key assumptions and equations of the Harrod-Domar model, which links the growth rate to the savings rate and capital-output ratio. However, the document notes that the Harrod-Domar model treats factors like the savings rate and population growth rate as constant, when in reality they may change as the economy grows, making them endogenous rather than exogenous variables.