p Investment Determination 5 In chapter 3, we have assumed that y 2 investment is autonomous and thus it is simply given. This is certainly not satisfying For a complete model of output determination, we need to discuss how investment is determined.Investment Determination • In chapter 3, we have assumed that investment is autonomous and thus it is simply given. This is certainly not satisfying. For a complete model of output determination, we need to discuss how investment is determined