Currently this site contains Excelets for teaching microeconomics: Principles, Intermediate, and perhaps beyond.  These Excelets are designed to illustrate core concepts.  Much microeconomics at this level deals with comparative statics.  A good student will work exercises with pencil and paper that involve setting up a model and either drawing the appropriate diagram to analyze that model or working through equations to do likewise.  Unfortunately, many of our students, at least the students I see in my classes, don't have the wherewithal to perform this sort of analysis.  They need some help.  The Excelets allow greater visualization of the concepts than can be achieved in a text based world.  Visualization is obtained through animation of the comparative statics results.  Students can view little graph movies by holding down control buttons that allow the the students to determine key parameter values.  The Excelets also promote Inquiry Based Learning by allowing students to ask "what if" questions and then being able to answer those within the context of the model. "What if I raise the tax?  What happens to the amount traded in the market?"  The traditional approach places demands on the students to go through (to them) an  elaborate procedure to answer the question.  With the Excelets the response is more immediate and that facilitates students going on to the next question.

Main Use Out-of-Class; Secondary Use for Presentations in Smart Classrooms

For those teaching in smart classrooms with computer and projection equipment, the Excelets can be used in presentation mode as means of illustration.  The intent in their design, however, was for Excelets to be used by students out of class, as they work to understand the material.  In order for this to be effective there needs to be exercises to accompany the Excelets.  Such exercises must be assigned for course credit.  An exercise helps the student focus on what to look at when considering a particular graphical situation by giving the student a problem that needs to be addressed, allowing the student to view the Excelet as a tool for solving the problem.  I have decided to keep such exercises separate from the Excelets.  Some of these exercises will be used in lab mode where the students can be instructed while they are sitting at the computer.  Also, I am in the process of constructing exercises that can be automatically evaluated by either  Blackboard or WebCT (course management systems  we support at UIUC).  A very nice site created by Byron Brown at Michigan State has the entire package in an integrated form. 

Visualization without Programming

Two reasons for the Excelets page are first to keep the focus squarely on the visualization of concepts and second to do this with essentially no programming at all.  My hope is that others (both economists and faculty in other disciplines where illustrating quantitative relationships is important for learning) will construct their own Excelets.  To achieve that end the Excelets must obviously help students understand concepts and the Excelets must be easy to make at a technical level.  Regarding the latter, the only technical requirement is a basic knowledge of Excel.   

What works visually to communicate the concept?

I also hope with this site to encourage practitioners such as myself to explore issues of effective ways to illustrate concepts and to gather experience about what works and what doesn't in designing this type of visual material.  For example, consider the module on the consumer optimum. There I made a point of identifying all tangency points between constraints and indifference curves as particles.  I believe that when students play a graph movie on the consumer optimum, their eyes follow the motion of the particle and at least in part abstract from the other data in the diagram. Is that what we want for illustrative purposes?  I am not sure.  I do know that is the sort of question we should be asking.  There are, of course, more fundamental issues: what to illustrate and what to ignore, what determines a good visual representation of an idea, and when should students be forced to make their own visual aids rather than rely on the ones we provide?  Perhaps the educational psychologists know the answers to these questions.  (Toward a Theory of Instruction, (1974) J.S. Bruner has some nice examples of good and less good ways to visualize concepts.)  But we don't have that knowledge.  And we are not likely to learn the answers by reading the research literature (though that certainly would help inform our thinking).  Because the answers are likely to be highly situation dependent, we need to design some of these and try them out in our own teaching and see what works and where there are problems.

Excel - an ordinary, commonly used tool

Why Excel? Why not Mathematica, Matlab, or some statistical software?  Here at UIUC the Economics department is in the College of Commerce and Excel is the tool of choice.  So here it is a no brainer.  What about elsewhere?  My belief is that MS Office has made sufficient penetration that we are, in essence, locked into that set of tools, like it or not.  Especially for faculty who have yet to seriously use technology in their teaching, showing the teaching benefits from tools they are familiar with from other contexts is a powerful way to encourage diffusion.  We have already gone through this with PowerPoint.  Faculty who have had to make short presentations at conferences learned to use the tool for that purpose.  Bringing that into the classroom was no great leap.  I believe Excel is next.  It has the same markings.  Then, too, the students need to know Excel.  If we're locked in, so are they.  The alternative is not for them to learn something better.  The alternative is for them to fall behind their peers for lack of knowledge of a core tool that has become the standard in the business world.  We have an obligation to provide students with meaningful content in Excel, so they gain familiarity with the tool.  Almost certainly, if they have a computer of recent vintage Excel is loaded on it.

Releasing Potential

What does using Excel buy us?  At its core, Excel is a tool that enables recursion and recursive analysis.  A good deal of economic dynamics is fundamentally recursion.  Excel allows us to introduce dynamic economic models into the Principles course.  Here it has the potential of completely changing the curriculum, by bringing in much greater realism early on and more strongly tying the models to reality.  My hope is that as we learn to create visualization with this tool, we also learn to bring in dynamic elements.