Intervening Variables Essay

413 Words2 Pages
Intervening Variable An intervening variable is one which interferes with the apparent association between two (or more) other variables. More generally this called a 'spurious' variable. Suppose you want to study the relationship between class size and how well students learn. You compare two classes, one small and one large.At the end of the term it is discovered that the students in the smaller class had better grades than those in the larger class. Your conclusion is that small class size indeed causes better grades. Wrong, because there is a fundamental problem with this conclusion; you did not account for 'intervening variables'! Could there be an intervening variable that is effecting this relationship between class size and student performance? Actually there can be many factors which are influencing this relationship. How about the influence of the teacher? Suppose it just so happened that the teacher in the small class is much better than the teacher in the large class and this is the reason why the students in the smaller class did well. The 'type of teacher' becomes an intervening variable because it was an important factor that was not initially considered by the researcher. Suppose that there were two different types of books used or two different types of curricula used? Suppose it just so happens that the students in the small class happen to be smarter than those in the large class? These are some obvious intervening variables, but there could be many more that are not so obvious. Suppose the teacher of the small class had brown eyes and the teacher in the large class had blue eyes? Could eye color be an intervening variable? Sounds preposterous, and it probably is but I ask you: "Can you cite a study done which demonstrates that the eye color of the teacher does not effect student performance"? The
Open Document