For students with some epidemiologic knowledge, Causal Pie Bingo! can be adapted to demonstrate the relationship between the sufficient component cause model (causal pies) and the potential outcome model (counterfactual).
We have found it easiest for the instructor to draw the counterfactual exposed/unexposed table on the board so that students can follow along. The instructor should choose 1 exposure (component cause) to be the exposure of interest and label the counterfactual table accordingly so there is no confusion. In this example, the exposure of interest is Stress.
Stress (E+) No stress (E-)
Type 1 (doomed) 1 1
Type 2 (causal) 1 0
Type 3 (preventive) 0 1
Type 4 (immune) 0 0
To determine which causal type they are, the player should first decide which 2 Types correspond to their actual game card and then decide what would have happened counterfactually (counter to the facts) had their exposure status been reversed. Their counterfactual experience will determine which of the causal types they are. The following is an example of how this determination might occur.
If Stress is colored in and they have the disease they are either Type 1 or Type 2. What would happen if Stress were not colored in? If they would still have the disease, they are Type 1. If they would not have the disease, they are Type 2.
If Stress is colored in and they do not have the disease, they would either be Type 3 or Type 4. What would happen if Stress were not colored in? If they would not have the idsease, they would be Type 4. If they would have the disease, they would be Type 3.
If Stress is not colored in and they have the disease, they are either Type 1 or Type 3. If Stress were colored in and they had the disease, they would be Type 1. If they did not have the disease, they would be Type 3.
If Stress is not colored in and they do not have the disease, they are either Type 2 or Type 4. If Stress were in and they still did not have the disease, they would be Type 4. If they had the disease, they would be Type 2.
Teaching points
A person's causal type is defined by the exposure of interest. For example, a player can be type 1 (doomed) with respect to Stress but type 4 (immune) with respect to Lack of Sleep. The instructor can choose a second exposure of interest and have players determine which causal type they are with respect to the second exposure and if their causal types are the same or different between these exposures.
A person's causal type with respect to a given exposure is not fixed and can change as their exposures change. In the poster available to download (see Citations), we provide an example of a player who has 3 different causal types with respect to the same exposure during the course of the game. The instructor can pause the game at multiple time points and determine which causal type each player is and if the players' types have changed since the last assessment.