I thought Noah Smith's post on why we should teach intro micro before intro macro was very good. I agree with Noah: even though macro is much more glamorous, micro is just as useful and important, and we are more confident that micro works. (Read his post for the full story.)
I want to add a couple of points in support of Noah, then talk about what I think is a bigger issue: the splitting of micro and macro into two separate half courses. I'm against splittism, but it's getting harder and harder to fight off the separatist forces.
Unlike Noah, who's just a young guy (judging from his photo), I speak from the vast authority of having taught intro (both micro and macro) about 30 times. So listen up, you kids.
Here are my couple of (related) points in support of Noah:
1. One of the most important things we teach in macro is the fallacy of composition. What is true of each of the parts isn't necessarily true of the whole. Just because the supply curves for apples, bananas, and carrots are all non-vertical does not mean the aggregate supply curve is non-vertical. The reasons the aggregate demand curve slopes down (if it does) are different from the reasons the demand curves for apples, bananas, and carrots slope down (except in a small open economy with a fixed exchange rate where it's basically the same reason). We can't just add up the supply and demand curves, because the things we are holding constant when we draw the curves for apples (like the price of bananas) are changing when we move along the curves for bananas. Each of those curves holds income constant, but income is changing as we move along the AD and AS curves.
If they didn't already understand micro, they wouldn't be able to understand what it means to add up micro to get macro. We wouldn't be able to properly teach the fallacy of composition.
2. The biggest of all macro questions is this: if you add up all the micro bits properly, so you avoid the fallacy of composition, why the hell does it seem not to work at the macro level? Or only work in the long run? (Or maybe it does work, if you are an RBC theorist who is determined to make it work?) It would be like if Newtonian mechanics worked OK for each individual car, but failed to work OK when you put a lot of cars together on a highway system.
If they didn't already understand micro, they wouldn't be able to understand that we have an empirical problem when we correctly (avoiding the fallacy of composition) add up micro to get macro. We wouldn't be able to properly teach the big macro problem of the trade cycle.
Now for the separation of intro micro and macro into two half courses.
At Carleton we have always taught intro as one full course. We do micro in the Fall term and macro in the Winter term. Usually, but not always, with the same instructor teaching both halves. But we face a lot of pressure from administrators, and students, to split it into two half courses, like most other Canadian universities. I can understand that pressure.
Maybe a transfer student has already taken micro at another university, and wants to complete just the macro half at Carleton, without repeating the whole course. Or vice versa. (We finally broke down and let them do this, because it was too embarrassing sending them down the canal to take the other half at University of Ottawa.)
Maybe a student is doing fine in the first half, but something goes wrong in the second half (maybe something totally unrelated to academic performance). Why can't we at least give credit for intro micro?
Maybe one half the course doesn't work with the student's timetable this year.
And so on. Everything is just so much more convenient all around if courses are broken up into easily-digestible bite-sized chunks. (The main data system, from the US, couldn't even grasp the concept of a two-term course, and had to be specially programmed to make it work.)
But I don't like the idea of splitting micro and macro into two half courses. It's just wrong. And it's wrong both ways, so simply making micro a pre-requisite for macro isn't the solution. Just as students can't understand macro without first understanding micro, they can't really appreciate micro without seeing where it fits into (or doesn't fit into) the big macro picture. (In that sense, I accept that the macro-first people do have a point.) I don't want to let any student out into the world until they have some idea of both micro and macro. They just do not have an introduction to either micro or macro unless they have seen the other side of the picture too, so they can understand how inadequate it is to see only one side of the picture. A little learning is, sometimes, a dangerous thing.
But I know I am fighting a lonely rearguard action to slow down the forces of progress and commonsense and what's best for students. They know I will retire soon, and will then do the sensible thing.
(P.S. I think it's correct to say that most teachers of intro, and most authors of intro textbooks, are more macroeconomists than microeconomists. Macroeconomists are more comfortable teaching basic micro than microeconomists are teaching basic macro. I think that tells us something important, though I'm not sure what.)