Teaching Random Assignment: A Classroom Demonstration Using a Deck of Playing Cards

Abstract

Despite its apparent simplicity, random assignment is an abstract concept for many students. This article describes a classroom demonstration that uses a standard deck of playing cards. In small groups, students randomly assign playing cards (i.e., participants) to 2 treatment groups. Following randomization, students compare the relative frequency of “background variables” across the 2 groups (e.g., the number of red, black, face cards, spades). A pretest–posttest design indicated that quiz scores increased following the demonstration. We suggest a number of possible extensions for the demonstration.