Frequently Asked Questions about Class Experiments
How do I make sure an experiment runs well?
Why should I use economics experiments to teach?
To begin with, there is evidence that the use of economics experiments actually improve student performance (Emerson and Taylor, 2004; Durham, McKinnon, and Schulman, 2007). Because students are actively involved in the experiment, the topic is more real to them, and they have a deeper level of understanding. By combining the experiment with guided discussion, students frequently discover some of the economic principles on their own, which further increases learning.
How should I reward student participation in experiments?
There are several approaches to this, and little agreement about what is the "best" way to reward participation. Here is an overview of your options:
How many experiments should I conduct in a semester?
While there is no exact answer to this question, it is probably best to not schedule too many experiments in a course if you have never run any before. Once you begin to use class experiments on your own, you will develop a better feel for how many you want to do, and you will also become more experienced and comfortable with running more experiments.
What if the results of an experiment are different than expected?
In our teaching modules, we present "typical" results from classroom experiments. For many types of experiments, results are quite consistent and so you can reliably expect to have similar results. However, sometimes you will see results that differ from what is expected. There is nothing wrong with this, and you can use it to your advantage to get students involved in the discussion. One approach is to present students with the unexpected results along with more typical results, and then discuss possible explanations for why the two data sets are different. Care should be taken that students don't feel that they made a mistake as they are should be encouraged to think about the reasons why they made their decisions, and why students in other classes may have made different decisions.
How do I make sure an experiment runs well?
While prior experience is usually the best way to insure experiments run well (just like with your lectures), there are several things you can do to make things run more smoothly:
How do I discuss the results of an experiment?
The post-experiment discussion is the time when you really can interact with your students, and you will find many students become quite engaged in the discussion. You should not be too willing to give away the story of the experiment by simply lecturing about the results. Rather, allow the students to discover and articulate to the class the central ideas of the experiment, while you help your students to articulate their thoughts about the experiment. You should have a set of key discussion points about the experiment, and redirect the discussion if necessary to hit all of your key points.
For examples, see our teaching modules. Many of them offer a plan that includes questions and typical student responses.
Where should I conduct the experiments?
Classroom: There are many hand-run experiments that can be conducted in any classroom.
Some instructors prefer to run experiments outside of classtime, and saving the regular class period for discussing the results of the experiment. They feel like this enables them to use these active-learning exercises without giving up valuable class time. Others prefer to conduct them in class. One colleague stated that she likes to run experiments in class because they have the "wow" factor; she describes this as the point in the experiment when students start to really understand the incentives, and feels that discussion right after the experiment (as opposed to a day or more later if the experiment is run outsidde of class) maximizes the impact.
Should I run computerized or hand-run experiments?
There is no simple answer to this question. Some instructors use only hand-run experiments, while others use only computerized versions, and still others use a combination. That being said, there are factors which will influence your own decision on this matter.
With hand-run experiments, you don't have to worry about having special computer equipment, internet connections, and figuring out how to set up the software to conduct the experiment. In addition, some instructors enjoy the direct interaction with students that occurs with a hand-run experiment (for example, having students shout out bids and offers in a market experiment).
With a small class, there are a wide variety of hand-run experiments that you can conduct, including market experiments, public goods, and game-theory experiments. In larger classes, it is harder to conduct hand-run experiments, but our teaching modules give some suggestions for larger classes. We also have an entry about this in our FAQ.
Computerized experiments make record-keeping easier, and allow the instructor to present results to students much more quickly and easily. Also, because the computer collects, collates, and organizes all of the data, these experiments typically can be conducted more quickly than hand-run experiments. In market experiments, for example, this means that you can conduct experiments with more rounds; this gives makes it easier for the market to converge to equilibrium and also allows you to add extra features to the experiment such as taxes or price controls.
Most instructors who use classroom experiments start with hand-run experiments conducted during class time. As you become more comfortable with classroom experiments you may want to try one or more computerized experiments.
Do I need IRB approval to conduct class experiments?
Many instructors think that you need to get approval from your University's Institutional Review Board only if you use cash rewards in your classroom experiments.
In fact, it really depends on your purpose for conducting the experiment and what you plan to do with the results.
According to Federal guidelines, IRB approval is required for any research involving human subjects, where reserach is defined as a systematic investigation designed to contribute to generalizable knowledge.
In other words, if you are using the experiment in a class, but will not use the results of the experiment in any other setting, this is not research and therefore does not require IRB approval. On the other hand, if you will use the results of the experiment when you make a presentation or to write a paper, then this is research and must be approved by your IRB. It does not matter whether or not you pay your subjects.
Can I run experiments in a large lecture class?
Absolutely! While some experiments are more manageable in small classes, there are a lot of experiments you can conduct in large classes.
One option is to conduct computerized experiments outside of classtime.
In addition, some of our teaching modules give suggestions for adapting experiments for use in large classes.
One technique that some instructors use is to put the experiment instructions online a day or two before class. You can tell your students that they must print out the instructions, read them, and bring them to class in order to participate in the experiment. This has the added advantage that you can go through the instructions more quickly if students have read them before class. Any students who do not bring instructions are told to sit in the back rows and observe the experiment, while those with instructions sit in the front and participate. Of course, in this case not all students gain the benefit of participating, all observe the experiment and can take part in the follow-up discussion.
Should an experiment come before or after a lecture on a topic?
Most instructors conduct an experiment before they lecture on the topic covered by the experiment. This has two advantages: