Framing, analysis, and modeling

Consider you were approached by the local water agency with the following request: “Help us! The farmers are telling us that they don't have enough water for their crops. We are really concerned that groundwater tables are dropping rapidly, even though we have done our best to encourage more efficient irrigation systems. Why are they dropping? We expected them to increase!” Now, how would you go about explaining the reasons for the declining water tables? Which methods would you use, which research design, in order to give the best possible advice to the water agency? These questions are the topic of this chapter.