Scriptapedia/Creating Causal Loop Diagram from Variable List

Creating Causal Loop Diagram from Variable List (Hovmand)

This can be used to introduce causal loop diagramming after a list of variables have been identified (e.g., from a variable elicitation, connection circle, or graphs over time exercise).

Status

Promising practice

Primary nature of group task

Convergent

Time

Preparation time: 10 minutes

Time required during session: 40 minutes

Follow-up time: 15 minutes

Materials

1. Flipchart paper for each group or large whiteboard/chalkboard (e.g., approximately 5 feet of horizontal space per group)
2. Markers

Inputs

List of variables (e.g., from variable elicitation, connection circle exercise, or graphs over time)

Outputs

Set of causal loop diagram

Roles

• Modeler/facilitator with experience drawing causal loop diagrams and comfortable introducing conventions

Steps

1. Introduce the exercise by reviewing the variable list.
2. Either in the same groupings or new groupings, instruct the teams to now construct a causal loop diagram based on the connection circles.
   • We’re now going to create a causal loop diagram identifying hypothesized causal relationships between variables. These conectionns can be based on the literature, your own research or conjectures.
   • To do this, begin by picking variables that are important and transferring them to [your sheet of paper/the whiteboard] and then drawing a casual arrow from the cause to the effect. Then add a plus or minus sign to indicate the direction of influence with plus signs representing change in the same direction or positive associations, and minus signs representing change in the opposite direction or negative associations. If you can’t decide if a link should be plus or minus, and this is because you’re not sure as a group, use a question mark. If it could be both, then draw two separate causal links, one positive and one negative.
   • As the number of links increases, look for positive and reinforcing feedback loops.
   • For example, as education increases, income increases, and as income increases, there are more opportunities for even more education. This represents a reinforcing loop because the direction of change is reinforced. This same loop can either be a virtuous cycle or vicious cycle. For example, if I lose my job and income decreases, it may limit my ability to get an education, which in turn may make it even hard to get a job or future promotion, and this in turn would lower my income (draw the CLD shown in Figure 1).

     

     Figure 1. Single reinforcing loop (R1)

   • Of course, this can’t go on forever (either in the vicious or the virtuous cycle). As I go to school and get more education, the hours per week that I can work decreases, which in turn leads to less income (draw the balancing loop so that the CLD matches what is shown in Figure 2). Notice that less hours per week leads to less income. The converse is also true, more hours per week leads to more income. This is what kind of link, plus or minus? Answer: plus, correct. However, now with less income, there is also a limit on education. This forms a balancing loop: as I increase education, my hours per week decreases, leading to less income, which then leads to a decrease in education. I started with an increase education and ended up with a decrease in education, hence the behavior of this outer loop counteracts or balances the initial direction of change.

     

     Figure 2. Reinforcing loop R1 with the addition of a balancing loop (B1)

   • Our goal in this exercise is to develop a causal loop diagram, meaning we’re looking to identify the individual linkages between variables as well as the loops. So a good strategy here is to look for ways to “close the loop”. We do this by looking for variables that don’t have any arrows going into them and seeing if there is another variable in our model that might influence this variable. If there is, we can then draw a link.
3. As groups work on their causal loop diagrams, facilitators walk around the room, observe how the groups are doing, and coach them. Consider the focus of coaching in three phases:
   • (beginning, first 5 minutes): focus on clarifying the instructions and provide positive reinforcement that they are on the right track. For example: "That looks great. You have several variables representing [topic] and causal links with polarities identified."
   • (middle): Focus on helping groups improve their skills in developing the diagrams and representing their discussion. For example: "Remember, if you want to show a relationship that goes in both directions, draw two separate lines," or "Seems like you’re having a lot of disagreement about whether the variable is the same for all communities. Why don’t you try adding a second variable and representing both ideas on the page, even if they feel a bit contradictory, or only relevant for some communities."
   • (end, last 5 minutes): look for a group that has a good example to start the next exercise, and role model how one explains the connections: "You have 5 minutes left before we return to large group," or "That looks great. I see how [variable 1] is influencing [variable 2], and this is influencing [variable 3], which then affects [variable 4]. You also have a couple of feedback loops. This one is reinforcing (point to loop and talk it through) and this one is balancing (point to loop and talk it through). Nice job!"
4. Tell the groups to stop after 15 minutes and ask each group to present their connection circles.
   • What were some of the main themes your group ended up discussing?
   • Where did you see the most interesting feedback loops?

Evaluation Criteria

• Participants created a rich causal loop diagram (CLD) based on their thoughts and stories
• Set of CLDs

Authors

Peter Hovmand 2017

History

This was originally based on the Hovmand and Kraus (2013) "Creating Causal Loop Diagram from Connection Circles" script as part of Raising St. Louis in 2013 where the connection circle exercise provided a "warm up" for a group and an initial set of associations for the CLD. This was found to be helpful for groups that tended to feel more comfortable in correlational thinking and the barrier too steep for jumping directly into operational thinking from the feedback perspective. However, relying on the connection circles as a starting point often meant that the group did not get a sense to develop a shared view of the dynamics of the system as might be typical through the graphs over time exercise. Although going from a graphs over time to connection circle exercise, and then from the connection circle exercise to a causal loop diagram might have been an option, it seemed that one might be able to go directly from graphs over time to causal loop diagramming with some groups. Hence, the basis for this script.

Revisions

None

References

None

Notes

1. Brian Biroscak <bbirosca@health.usf.edu> created a variation of this script using a different example for a CLD ("Why did the chicken cross the road?") as part of the CDC funded University of South Florida Prevent Research Center. This exercise worked much better with some cross-cultural adaptations and has been tested in both India and China.