Teaching about Variables

The concept of a variable is something that students in my methods course have trouble understanding. The difference between a variable and a constant, what a value is or how a variable can be measured in different ways with different sets of values–all of these things they find very confusing and abstract. I have two ways of dealing with this. First, I ask them to imagine they are in a room filled with toys for children with a series of unlabeled toy boxes lining the walls. It is their task to put the toys away (note: you can make this an interactive, hands-on experiment either by bringing in some toys yourself, or in a brilliant stroke of work-life balance, asking your students over to clean up your kid’s playroom/bedroom). Ask them how they organize the toys as they put them away. They tend to volunteer answers like ‘by size’, ‘by age range’, ‘by color’, ‘by purpose’. You can point out that the organizing system is the variable, and the labels they put on the actual toy boxes–large, medium, small, or educational toys, or toys for infants–are the values that the variable can take. Start with this example, and then whenever you are working with a variable, you can replace the toys with the variable in question. Toys can become regime types, with toy boxes labeled ‘democracy’ or ‘authoritarian’, or they can become ‘vote choices’ with candidates names appearing on the imaginary labels. Just as a framework for understanding this central concept, this thought experiment can work really well.

A more active way of doing this (besides my obvious joke about having your students tidy your house) would be to bring in a deck of cards and pass out a card to each student and then invite them to group them together any systematic way they choose, with the rule that there must be at least one group and that to start, at least, each group must have at least two cards. Once they are done, they have to tell you the category by which they chose to organize the cards, and how they would label each group. Write the method on the board, then have them do it again three or four times. With a deck of cards, there are a lot of organizing systems–by suit, by number, by face card v. number, by color, by odds and evens–by the end of the exercise, they see how you can gather multiple variables about the same information or data points, and that you can measure them in different ways. For example, if they organize by number, they can do cards from 1-3, 4-6, and 7-9 or from 1-5 and 6-10 (I usually leave out face cards with a small group).

From either of these, you can then easily define variables and values and start talking about them in a political context or move into discussing hypotheses or measurement. I’ve used the toy box example in three different sections with great success; I just tried the card example and the students definitely seemed less confused then in the past when I’ve tried to work with them on this building block of methodology.