Why do economists keep changing their models? It seems like they tell a story, and then some number of years later (yes, sometimes it takes a while) they tell a new story that looks very different. It seems like they don't know what they're doing."

Recognize that that your audience does not understand those terms, so you should either provide definitions or explain the principle without the term.

In all writing assignments, you are to write two paragraphs. First, identify key topics and terms to clarify and discuss what clues led you to choose those.  Part one should be written for a group of co-workers as if you are on a team of analysts. Part two should be written for someone who would ask the question and does not know the answer already.