A traditional epidemiological study may show increasing rates of malaria in a region, but not address the reasons for the increasing rate; an environmental health study may recommend the application of a pesticide in specific amounts in certain areas to reduce spread; an economic analysis may calculate the cost and effectiveness of such a program.
An epidemiological study may show increasing malaria cases, but it won't necessarily pinpoint why they are rising; an environmental health study might recommend using pesticides in specific amounts in particular locations to decrease spread; an economic analysis would assess the costs and benefits of implementing such a strategy.