Causal Link Guidelines
An “S” or “+” indicates that the variables change in the same direction (both go up or both go down) or a change in a variable adds to the following variable.
An “O” or “-” indicates that the variables change in opposite directions or a change in a variable subtracts from the following variable.
When drawing cause → effect linkages between variables, use arrows to show the direction of causality. The arrowheads are labeled to show the relationship between the variables.
HINT: To create your labels, always start with the assumption that the first variable goes up.
Let’s use a dental example of variables that include sugar intake, the development of new cavities and teeth brushing.
So, if sugar intake goes up, then what happens to cavities (all else being equal)? They also go up, so the link is labeled with an “S” or “+” sign.
Tell the story: As sugar intake increases, the potential for new cavities increases.
Tell the story: When people continue to brush their teeth, the potential for new cavities decreases.