Activity 7: Limitations of Systems Diagrams

Cameron Weiner - Undergraduate - Middlebury College,

Lisa Gilbert -Professor of Geosciences and Marine Science - Williams-Mystic,

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This activity teaches students about the value of planning, knowing, and explaining the limitations of a systems diagram. Students are taught to follow the following four steps when assessing the limitations of a systems diagram: identify the question, identify the scope, identify the missing sources, identify the level of detail. Students then assess the limitations of a systems diagram they previously created, and reflect on how assessing the limitations of a systems diagram also allows them to identify ways to improve their systems diagrams.

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This activity is intended for a middle school science course. Materials presented here are designed to be implemented in a remote learning environment, either as part of an entirely online or hybrid course. This activity is designed to pair with and be a reflection on a previously completed systems diagramming activity.

Skills and concepts that students must have mastered

Students need to have previously created a systems diagram or other form of model.

How the activity is situated in the course


Content/concepts goals for this activity

  • Students will learn how to assess the limitations of a systems diagram.
  • Students will assess the limitations of their own systems diagrams.

Higher order thinking skills goals for this activity

Other skills goals for this activity

Description and Teaching Materials


Activity Description (total time: 30 min)

Part 1 - Limitations Brainstorm and Importance (7 min)

The instructor begins to screen share the Limitations of Systems Diagrams Powerpoint.

Slide 1: Topic introduction - Limitations of Systems Diagrams. What's missing and why?

Slide 2: Students are instructed to open the last systems diagram they made and Student Handout Activity 7. This could be a systems diagram from Activity 3, 6 or 12 or an outside activity. This activity was specifically created with the diagram from Activity 6 in mind.

Slide 3: The instructor asks students to answer Question 1 of the handout: What stopped you from making the systems diagram you wanted to make? Students take 2 minutes to write down their thoughts.

Slide 4: Students discuss their answers to Question 1 as a class. The instructor might need to prompt students to think about things like the software they made their diagrams on or the information they were provided.

  • Examples of limitations: The diagram software (LOOPY) not providing enough space to include all the necessary system elements, being confused about the system you were diagramming due to a lack of background knowledge or provided information, not having sufficient time to create the diagram, etc.

Slides 5-7 explain that  importance of recognizing and understanding the limitations of a systems diagram:

Slide 5: The instructor explains that the items mentioned in the class brainstorm are called limitations and that recognizing and understanding the limitations of a system is important.

Slide 6: The instructor explains that recognizing and understanding the limitations of a systems diagram is important because recognizing limitations make our diagrams more accurate and comprehensive.

The instructor might say:"It's important because explaining our diagrams limitations, or where our diagrams are missing information, makes our diagrams more accurate and - our diagram goal - comprehensive."

Slide 7: The instructor explains that diagrams will never be able to represent an entire system perfectly because entire systems are much to complex and large. Systems diagrams can only represent parts of the system. And when you acknowledge where a diagram leaves out information or could be improved your diagram is more accurate and comprehensive.

The instructor might talk through slide 7 like this: "There are many different factors that limit our ability to represent a system. Some of the limitations you have already mentioned: the platform (LOOPY) that you made the diagram on was too small, you weren't given enough information or explanation, you weren't given enough time to complete your diagram, and the list goes on. But even with the perfect design software, loads of time, and lots of information, systems are still too complex to represent perfectly. 

As you'll see on the next slide, systems are way too complex to represent 100% perfectly or 100% completely. So we can only ever represent certain parts of a system, not the entire system in all its complexity. But if we don't state the information that is missing from our diagrams we are claiming that our diagrams are perfect or 100% complete, which is very inaccurate."

Slide 8: A chaotic LOOPY diagram of the wastewater system from the Answer Key Septic Student Handout Activity 6. Prompts students to think and share about how systems can be infinitely complex.

How the instructor might use this slide: "Take this systems diagram of the wastewater system for example. This is already a pretty complex system, but think about how much information this diagram is still missing. Comment in the chat or call out where more details or information could be added to this diagram. [provide time for 5+ student responses] See! The amount of detail that you could add to this diagram could go on forever! We will never be able to perfectly represent this entire system because it goes into infinite detail and is interconnected with an infinite number of other systems."

Slide 9 contains a question prompting students to think about how we make decisions on what information we not to include or don't include in our diagram: What information is missing from our diagram and why?

How the instructor might use this slide: "So once we make a diagram that is inherently incomplete, the next question on my mind is: How can I explain what information is missing from my diagram and why?"

Part 2 - Steps to assess the Limitations of a systems diagram (18 min)

Slides 10 - 29 walk through the steps students can take to assess the limitations of their diagrams. The instructor demonstrates how to complete each step using a simple LOOPY diagram provides an example of the school water supply system. The instructor can substitute this example for a variety of other simple diagrams of systems the students are familiar with. After each example is explained, the students practice completing the step with their own systems diagram on Part B of the Student Handout Activity 7.

Click here for an example script of how an instructor might walk through slides 10-29.

Part 2 - Reflection(5 min)

Slide 30: The students reflect on the process of assessing the limitations of their systems diagrams with a question for class discussion: How did assessing the limitations of your diagram help you identify ways to improve it? The instructor provides the class with 5 minutes to discuss or asks students to discuss in a breakout group then as an entire class.

Teaching Notes and Tips

The systems diagrams that students are assessing and the example systems diagram that the instructor uses in this activity can be easily adapted to an example that best suits the instructor's course.
Students could complete Part 1 prior to and complete Part 3 as a question following class if the instructor does not have sufficient class time to complete the entire activity.


References and Resources

This systems thinking module is based on the undergraduate Systems Thinking module on InTeGrate, created by Lisa A. Gilbert, Deborah S. Gross & Karl J. Kreutz. This rates and quantities experiment relates to Unit 5: Analyzing Complexity.

Systems Thinking Vocabulary Glossary

Why teach students to assess limitations of systems diagrams?

NGSS crosscutting concepts: End of 8th grade: "Models are limited in that they only represent certain aspects of the system under study."

Limits as a form of student self-evaluation: Lally, Diane, and Cory T. Forbes. 2020. "Sociohydrologic Systems Thinking: An Analysis of Undergraduate Students' Operationalization and Modeling of Coupled Human-Water Systems." Water 12 (4): 1040.

Why teach systems thinking or the water supply chain in Middle School?

"Appendix G - Crosscutting Concepts." 2013. Next Generation Science Standards.

Learn about why we should teach Systems Thinking in Earth Science:

Learn more about teaching systems thinking:

Learn more about systems thinking:

  • Meadows, Donella H., and Diana Wright. 2008. Thinking in Systems: A Primer. White River Junction, Vt: Chelsea Green Pub.