A test of the relative effectiveness of using systems
simulations to increase student
understanding of environmental issues
Heather Skaza and Krystyna A. Stave
University of Nevada Las Vegas
Department of Environmental Studies
4505 Maryland Parkway Box 454030
Las Vegas, Nevada 89154-4030
702-895-4833 (office) and 702-895-4436 (Fax)
hiskaza@ hotmail.com, krystyna.stave@ unlv.edu
Abstract
This paper reports on an experimental study testing the relative effect of using
simulation models on systems thinking in a college-level Introduction to
Environmental Science section. The preliminary findings show mixed results. It
is unclear whether this is a result on the systems simulations used in the
interventions or the assessment techniques employed to study their
effectiveness.
Key words: education, environmental science
Introduction
Educators in the system dynamics community have long supported the notion
that systems thinking skills are an essential part of education. Systems-oriented
education gives “student s a more effective way of interpreting the world around
them” (Forrester, 2009 ). Systems-oriented education supports active learning
(Grant, 1997). Diana Fisher states that in her classroom experience “students
learn effectively when they are actively engaged in building skill when working
with abstract concepts"(2008:1) Research supports active versus passive
learning in increasing student motivation (Cherney, 2008). Students involved in
active learning techniques have also demonstrated greater retention of course
material (Benware and Deci, 1984). System dynamicists agree that systems
thinking skills increase understanding of complex problems (Maani and Maharaj,
2004). This is particularly useful in environmental education as environmental
systems are very complex and often produce results that are difficult to predict
(Grant, 1998).
Although systems dynamicists agree that systems thinking skills are effective in
tackling complex problems, few studies give quantitative evidence of the
effectiveness of systems interventions (Doyle, Radzicki and Trees, 1998). In
Doyle’s words, ‘there is insufficient evidence to convince skeptical, scientifically
minded observers, which is crucial if systems thinking ideas and techniques are
to become more widely accepted in educational and corporate
settings”(1998:254). A larger base of empirical evidence supporting systems
thinking as a tool to increase understanding of complex issues is crucial to
developing effective interventions.
This paper reports on an experimental study testing the relative effect of using
simulation models on systems thinking in a college-level Introduction to
Environmental Science section.
Problem Statement/Research Question:
Researchers have studied systems thinking and system dynamics in various
classroom settings. Hopper and Stave (2008) identified fourteen studies that
tested systems thinking interventions in the classroom, from kindergarten to the
postgraduate level. Most of the studies evaluated students’ ability to understand
dynamic behavior and their ability to differentiate types of variables and flows.
Both of these are intermediate systems thinking skills, as described in Stave and
Hopper's proposed systems thinking taxonomy (2007). Very few studies
examined the lower level skills of the systems thinking taxonomy.
The purpose of this study was to test the effect of using systems simulations on
students’ systemic understanding of environmental issues in an introductory
environmental science course. This research supports two goals. One is to
develop better tools for increasing systems thinking skills through the use of
simulations. The other is to improve methods for assessing a change in systems
thinking capabilities.
We asked the question: Does the use of systems simulations in an introductory
environmental science course affect the students’ systemic understanding of
environmental issues? Another question that emerged in developing the study
was: Are current methods of assessment effective in measuring a change in
systems thinking abilities?
Hypothesis:
Our hypothesis at the outset of the study was that the students that used
systems simulations in conjunction with lecture material would demonstrate
greater systemic understanding of environmental issues than the students that
were enrolled in the lecture-only section.
Method
The study was conducted on about 209 students enrolled in four sections of an
Introduction to Environmental Science course in the spring of 2009.
Demographic data shows that students in all four sections were similar in age
distribution, environmental education level and motivation for taking the class.
The four sections were live lecture classes. Class size varied. The classes had
51 students, 107 students, 52 students and 89 students. At the beginning of the
semester, two sections were chosen at random to be the experimental sections.
The other two sections were the control sections. The experimental section had
107 students and 89 students.
All four sections had five main educational components: assigned text book
readings, lecture material, five assignments based on the readings and lecture,
and four quizzes, and a final, comprehensive quiz at the end of the semester.
The experimental sections used systems simulations to complete three of five
assignments about an environmental issue presented in class. The control
sections completed the same assignments, but with only a text description of the
issue.
Course lecture material was based on an introductory text book and covers a
variety of topics in the environmental sciences. The text and lectures paid close
attention to the human relationship with the environment and particularly to how
human activities impact the natural world and what services are provided to
human beings from the natural world. All sections had the same text book.
All sections were team-taught by three instructors, but all received the chapter's
lecture from the same instructor.
Assignments:
The five assignments were designed for students to consider their role in
environmental issues. Of the five assignments, three used a systems simulation
to enhance lessons taught in class. For those three assignments, the
experimental sections used the simulations to complete questions about the
environmental issue covered. The control sections were given an equivalent text
description of the issue and asked to answer the same questions. Table 1
describes the five assignments and what kind of simulation was used.
Table 1: Description of simulations used for each class assignment
Assignment
Simulation used
1: Students watched a
video about the
ecological footprint and
the used a web-based
calculator to calculate
their own.
Web-based ecological footprint calculator with graphics
2: Students were asked
to describe the effect on
total population when the
number of births and
number of deaths ina
population are increased
or decreased.
An original model was created with total population as
the stock and number of births and number of deaths
as the inflow and outflow.
3: Students were asked
to manage a herd of
reindeer so that the
lichen that is their primary
food source is not
overgrazed.
Sawicka and Kopainsky’s (2008) model of reindeer
herd/lichen dynamics gives student a tutorial on how to
manage the reindeer herd and instructs them to decide
on herd size every year for fifteen years to maintain
lichen growth at an optimum for their survival.
4: Students were asked
to test out carbon
emissions levels and
note the effect on CO2 in
the atmosphere.
Sterman’s (2006) bathtub model allows students to
increase and decrease carbon dioxide emissions. The
output graph simulates atmospheric CO2 levels over
time. Computer graphics depict rising level in a bathtub,
representing rising carbon dioxide level in the
atmosphere.
5: The Story of Stuff
video and reflection
None
We focused on Assignments 2 and 4 for this study. Systems underlying the
simulations used in these two assignments were similar in structure. Assignment
2, Population Dynamics and Assignment 4, Carbon in the Atmosphere, used
one-stock, two-flow systems to explain the concept of accumulation. We were
able to assess the same systems thinking skills, asking similar questions in
different contexts.
Assessments:
Students were given a baseline assessment, four quizzes and a final exam. Each
quiz contained about 20 questions that were either multiple choice or short
answer. Multiple choice questions were either a question to be answered ora
prompt to be completed. Five answer options were given with one clear, correct
answer. Short answer questions asked the students to describe a concept ina
few sentences.
Questions on the baseline assessment and the final exam were used as pre- and
post test measures of systems thinking skills. The questions assessed students’
ability to recognize interconnections, differentiate between stocks and flows and
understand the way something in the system accumulates. The questions
focused on assessing these abilities in the context of the topics covered in the
assignments.
The first question focused on population change and was a short answer
question. The question used a graph of total population, birth rate and death rate
through four socio-economic stages: pre-industrial, transitional, industrial and
post-industrial. In the pre-industrial stage birth rate and death rate are both
relatively high and stable, causing total population to remain relatively low and
stable. In the transitional phase, death rate drops, while birth rate remains high,
causing total population to increase. During the industrial stage birth rate drops
to a level just above death rate and total population continues to increase, but at
a slower rate. In the post-industrial stage, birth rate drops below death rate and
there is a decrease in total population. Students were asked why, if birth rate is
falling in stage 3 (the industrial stage), population is still increasing? The correct
answer would state that the reason total population decreases is because birth
rate is still less than death rate.
A multiple choice question asked students to complete the phrase, ‘To reduce
the amount of greenhouse gas in the atmosphere, we need to...” Five answer
options were given:
a. Reduce the amount we add to the atmosphere each year by only 10
percent.
b. Do nothing; the level of greenhouse gases in the atmosphere is
decreasing naturally.
c. Make sure the amount added to the atmosphere is less than the
amount that is removed.
d. Itis not possible to reduce the amount of greenhouse gases in the
atmosphere.
e. None of the above.
The correct answer is c. Make sure the amount added to the atmosphere is less
than the amount that is removed.
The final exam also included a diagram with one inflow, one outflow and one
stock. There were three questions associated with this diagram. Two multiple
choice questions asked students to identify the inflow/outflow conditions
necessary for the stock to increase and decrease. The last questions asked
students to explain, based on the given framework, what would have to be true of
emissions and removal in order for carbon in the atmosphere to decrease.
Table 2-Systems-oriented assignments and what skills they test
Assignment
Task in assignment
Systems thinking skill
assessed in quiz
2: Population dynamics
Students were asked to identify the correct trend, out of
four options, for total population change over time for a
given rate of ‘number of births’ and ‘number of deaths.’
Model users were then instructed to simulate each
condition with a model provided online and comment on
the results.
-Recognizing
interconnections
-Identifying stocks and
flows.
-Understanding
accumulation.
4: Climate change
Models section students were directed to The Climate
Bathtub Animation. They completed the model activity
online, and then were asked to reflect on carbon
emissions, absorption and their relationship to carbon
dioxide levels in the atmosphere. They were also asked
what would have to be true for carbon dioxide levels in
the atmosphere to decrease.
-Recognizing
interconnections
-Understanding stocks
and flows.
-Understanding
accumulation.
Evaluation
Each question was evaluated to determine which systems thinking skills it
assessed, that is, which systems thinking skill would be demonstrated in a
perfect answer.
Booth Sweeney and Sterman scored participant understanding of systems
concepts on five levels for open-ended, interview questions (2007). Following
this model students’ answers were given a score of 0, 1, 2, 3 or 4, based on the
systems thinking skills demonstrated in their answer. The previous study coded
answers based on a full range of systems thinking abilities. Our study focused
on only the most basic skills. The four tiers of understanding are based on the
four systems skills established at the beginning of the study: no systems
understanding, recognizing interconnections, understanding stocks and flows
and understanding accumulation.
No answer or an answer of ‘I don’t know’ received a Level 0 score. Level 0 was
also assigned to answers that did not recognize any interconnection or influence
of one part of the system in question to another.
The first level of systems thinking is recognizing interconnections. If an answer
demonstrated this skill, it was assigned a value of 1. Examples of phrases that
indicated a student's ability to recognize interconnections are “A causes B,” or “If
X, then Y,”“A change in A causes a change in B.” The interconnections
identified did not have to relate stocks and flows in the system. For example,
carbon in the atmosphere increases when carbon emissions are greater than
carbon removal, however students would often describe a change in carbon in
the atmosphere in terms of human activity that contributes to carbon emissions.
An example would be ‘Too many cars on the road increase carbon in the
atmosphere.” This student understands a causal connection, but has not proved
that they know the structure of the system.
The second level of systems thinking is understanding stocks and flows. An
answer was assigned a value of 2 if it demonstrated the students’ understanding
that one type of variable causes something to accumulate and one type of
variable accumulates. Answers that demonstrate this ability might describe one
variable as adding to another. An example answer for the population activity is
“a high birth rate causes total population to increase.” This student recognizes
which variable is a flow and which variable is a stock and recognizes the casual
relationship between the two.
The third level of systems thinking is understanding accumulation. The
mechanism may be different for different system structures. The systems
underlying the simulations in this study have one inflow and one outflow. In order
to understand how the stock in that system accumulates, the student must
understand how each part of the system relates to the others. An example
answer, using carbon in the atmosphere, would be “Carbon emissions must be
greater than carbon removal in order for carbon in the atmosphere to increase.”
Multiple choice questions were evaluated as correct or incorrect. If the student
answered the question correctly, they demonstrated the systems thinking ability
assessed by that question.
Short answer questions asked students to explain a concept. For each question,
a perfect answer required the ability to recognize interconnections, understand
stocks and flows and understand accumulation. Answers were scored based on
the systems thinking skills they demonstrated.
We compared average pre-test and post-test scores for a sample of fifteen
students from each section, for a total of 30 participants in the experimental
group and 30 participants in the control group. To ensure equal distribution of
general student performance level, we looked at students’ overall course grade
and randomly chose five high-performing, five average and five low-performing
students from each section. High-performing students achieved a final course
grade of 80 percent or higher. Average performance was defined as 70 to 79
percent. A low performance was defined by achieving a score of 69 percent or
lower. This was reasonable, as course grades followed a typical bell curve
distribution.
Results
Question 1 asks students to complete the phrase ‘To reduce the amount of
greenhouse gas in the atmosphere, we need to...” Students should have chosen
the correct answer from five options. The complete question and answer set can
be found in the appendix.
Table 3 shows the pre-test and post-test results for Question 1. The control
group showed a larger increase in the percent of students who answered the
question correctly. 43.3 percent of the control group students answered the
question correctly on the pre-test and 53.3 percent of the students answered
correctly on the post-test, for an increase of 10 percent. 40 percent of the
experimental group’s students answered the question correctly on the pre-test,
while 46.7 percent answered correctly on the post-test, for an increase of 6.7
percent.
Table-3 Pre- and post-test results for Question 1
% Correct | % Correct
9
Pre test Post test % Increase
Control Group 43.3 53.3 10.0
Experimental
Group 40.0 46.7 6.7
Table 4 shows the pre-test and post-test results for Question 2: If birth rate is
falling in stage 3, why is total population increasing in stage 3? Both groups
demonstrated an increase in the number of students who answered Question 2
using upper level systems thinking skills. The control group showed a greater
increase than the experimental group, increasing from a pre-test percentage of
53.3 to a post-test percentage of 76.6. The experimental group increased from
66.6 percent, pre-test to 73.3 percent, post-test.
Table-4 Pre- and post-test results for Question 2
Pre test Post test
% Level 2 or 3|% Level 2 or 3 % Increase
Control Group 53.3 76.6 23.3
Experimental
Group 66.6 73.3 6.6
The last three questions were only administered on the final exam. For these
questions the experimental group is compared to the control group. Table 4
shows the control and experimental class results for the last three questions.
The first question was multiple choice and asked students to identify the correct
inflow and outflow conditions for a stock to increase. The control group
outperformed the experimental group, with 93.3 percent of the students
answering correctly. 86.6 percent of the experimental group's students
answered the question correctly.
The second question was multiple choice and asked students to identify the
correct inflow and outflow conditions for a stock to decrease. The experimental
group outperformed the control group, with 40.0 percent of the students
answering correctly. 36.6 percent of the control group’s students answered the
question correctly.
The third question was short answer and asked student to explain what would
have to be done to decrease carbon in the atmosphere. The experimental group
outperformed the control group. 73.3 percent of the students in the experimental
class delivered a Level 2 or Level 3 answer, compared to 66.6 percent in the
control group.
Table-4 Pre- and post-test results for Question 2
Stock increase Stock decrease co2 foeners
(Multiple choice) | (Multiple choice) (Short answer)
% correct % correct % Level 2 or 3
Control Group 93.3 36.6 66.6
Experimental
eroils 86.6 40.0 73.3
Discussion
The data has produced some results that we expected to see and some results
counter to what we expected. As with preliminary studies conducted in the fall of
2008, the experimental group did not consistently outperform the control group.
The hypothesis, in this case, was not supported.
Systems understanding increased noticeably for both groups, after instruction
using to systems thinking skills. The control group was exposed to these skills
textually, while the experimental group received some textual instruction, but also
explored the concepts using a computer simulation. Both methods proved
effective in increasing systems thinking ability.
Our hypothesis was not supported for two reasons: first, there were problems
with the interventions conducted in class; second, there were problems with the
assessment methods used to measure students’ systemic understanding of
environmental issues.
Intervention improvements
The Introduction to Environmental Science class was a semester long, or about
four months. In that time, we used two assignments to introduce systems
thinking concepts. We feel that more interventions would have been effective in
increasing students’ systems thinking abilities.
For some students the mechanics of operating the model seemed to distract from
the lessons the simulation was intended to teach. Assignments used as
interventions in the future should follow the same format to eliminate as much
‘noise’ as possible. The format would become clearer with each successive
assignment.
Each assignment should be designed to look the same, relate the same concepts
and have the same method of operation. This would be best accomplished by
creating each assignment's reading material, simulation model and interface.
For this study, we created the population activity, but used The Climate Bathtub
Animation for the second assignment, as it was already available online. We
designed questions to accompany the simulation activity that required students to
think about the system structure underlying the simulation. Although the
simulations had similar structures, they presented in very different ways, masking
their similarities.
Assessment improvements
There were too few questions asked assessing students’ systemic
understanding. Future studies should include more pre-test/post-test questions.
It would be easier to note any kind of trend in students understanding if more
questions were used. Itis hard to say conclusively, from just four questions,
whether a student had a change in understanding. In many cases the same
student answered some questions in a way the demonstrated a high level of
understanding and some questions in a way that demonstrated little or no
understanding. If more pre-test and post-test questions were asked, we could
get a better sense of students’ overall understanding.
If multiple choice questions are used, there need to be several of them. Again,
this allows for trend recognition and eliminates skewing data when correct
answers are chosen by chance.
10
Student performance on Question 3 and Question 4 tells us two things: first,
when multiple choice questions are used in the assessments, all of the answer
options should be delivered in the same format; second, students are less able to
identify the correct answer when the answer option is numerical.
Question 3 asks students to identify the inflow/outflow conditions necessary for
the stock to increase. Question 4 asks students to identify the inflow/outflow
conditions necessary for the stock to decrease. The questions were worded
identically and their answer options were the same. Figure 1 shows Question 3,
Question 4 and the answer options given for both.
The results in Table 3 show that students performed very differently on these two
questions. On Question 3, 93.3 of the control group’s students and the 86.6 of
the experimental group's students chose the correct answer. On Question 4,
36.6 of the control group’s students and 40.0 percent of the experimental group’s
students chose the correct answer. The reason for the difference can be found
in the way that the correct answer is expressed. The answer for Question 3 is c.
RATE OF REMOVAL <RATE OF ADDITION. For Question 4, the answer is
RATE OF ADDITION =1,000,000 and RATE OF REMOVAL =1,000,001. Both
answers express the correct idea to answer the question, but students were less
able to identify the correct answer that was numerical.
Figure 1-Questions 3 and 4 and answer options given for both
3. Under what conditions would the amount of the thing in the environment
increase?
4, Under what conditions would the amount of the thing in the environment
decrease?
RATE OF ADDITION =1,000,000 and RATE OF REMOVAL =1,000,001
RATE OF ADDITION =RATE OF REMOVAL
RATE OF REMOVAL <RATE OF ADDITION
RATE OF REMOVAL >RATE OF ADDITION
Cannot be determined with the information given.
pans
In future studies, we would also include more ‘generic structure’ questions.
Student answers showed a tendency toward explaining the behavior of a system
not in terms of the structure they were given, but in terms of human behavior they
are already familiar with. For example, in defining what would cause a decrease
in carbon dioxide in the atmosphere, students were more likely to recommend a
decrease in driving automobiles or a decrease in industrial activity than they
would be to discuss the relationship between carbon emissions and carbon
removal. One hypothesis as to why this occurred is that students may have
already had a mental model of the systems used in the assignments. Using
generic system structures, such as the ones described for Questions 3 and 4
11
would direct students to focus on the system’s structure and not on what they
may already know about the system.
Evaluating understanding
For this study, we evaluated student responses to short answer questions using
the four levels of systems thinking previously explained, with the first level being
no systemic understanding at all. As answers were evaluated, more subtle levels
of understanding emerged than the four that we initially set out to evaluate.
1) Recognizing interconnections: Students could identify effect of
changes in one part of system on another.
> Example answer: Driving cars causes there to be more carbon in
the atmosphere.
2) Understanding the effect of one flow independently on its related stock:
describes the impact of changing either the inflow or the outflow on the
stock in the system.
> Example answer: An increase in carbon emissions causes an
increase in carbon in the atmosphere.
3) Understanding the effect of both flows on their related stock: student
relates both the inflow and the outflow to the stock in the system.
> Example answer: We would have to increase carbon removal and
decrease carbon emissions for carbon in the atmosphere to
decrease.
4) Understanding how the stock accumulates in the system under equal
inflow and outflow conditions: student could identify no change in the
stock when given equal inflow and outflow and vice versa.
> Example answer: The number of births would have to be equal to
the number of deaths in order for population to stay the same.
5) Understanding how the stock accumulates in the system when inflow
and outflow are not equal: student could identify an increase or
decrease in the stock for a given set of inflow and outflow conditions
and vice versa.
> Example answer: The number of births would have to be greater
than the number of deaths in order for total population to increase.
Students’ systemic understanding seemed to progress through these five levels
for questions about one-stock, two-flow systems. This information could be very
useful in evaluating students’ systemic understanding in future studies.
This study continues the work of determining the most effective way of increasing
systemic understanding of environmental problems in that it tested the effect of
systems interventions on a large audience. The preliminary findings show mixed
results in the effectiveness of using computer simulations for such a large group,
but the introduction of basic systems thinking skills produced a noticeable
12
difference in systemic understanding of environmental problems for both the
control and the experimental groups.
13
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14
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15
Appendix— Questions, correct responses, and systems thinking
skills required to answer question correctly
1. The demographic transition graph below shows the relationship between birth
rates, death rates and the overall size of the population at different stages of a
society's economic development. Use the graph to answer the next three
questions.
STAGE 1 STAGE 2 STAGE3 STAGE 4
Preindustrial Transitional Industrial Postindustrial
= A \ quia 3 a \
80 r : High
Birth and death rates
(number per 1000 population)
Relative population size
1© 2008 John Wiley & Sons, Inc.All ights reserved.
The birth rate is falling in STAGE 3. Why is the size of the population increasing
in STAGE 3?
Even though birth rate is decreasing, itis still greater than death rate. As
long as birth rate is greater than death rate, total population will increase,
because more people are being added than taken away.
Systems thinking skills required:
-Recognizing interconnections.
-Understanding stocks and flows.
-Understanding accumulation in the system.
2. To reduce the amount of greenhouse gas in the atmosphere, we need to...
a. Reduce the amount we add to the atmosphere each year by only 10
percent.
b. Do nothing; the level of greenhouse gases in the atmosphere is
decreasing naturally.
c. Make sure the amount added to the atmosphere is less than the
amount that is removed.
d. Itis not possible to reduce the amount of greenhouse gases in the
atmosphere.
e. None of the above
16
Systems thinking skills required:
-Recognizing interconnections.
-Understanding stocks and flows.
-Understanding accumulation in the system
For questions 3-5: Many environmental issues involve managing the
accumulation of something in the environment. We generally want to increase
the level of things we consider good, or valuable, and decrease the level of
things we consider bad, or harmful. Some of the things we consider good are the
amount of nutrients in the soil or level of dissolved oxygen in water. Some of the
things we consider harmful include pesticides in the environment, or carbon
dioxide in the atmosphere. We manage the levels of things in the environment by
controlling the rate at which we add to the level or the rate at which we remove
things, or some combination of the two. Use the diagram below to answer the
next three questions.
Amount of
—>> something in the
environment
RATE OF RATE OF
ADDITION REMOVAL
3. Under what conditions would the amount of the thing in the environment
increase?
a. RATE OF ADDITION =1,000,000 and RATE OF REMOVAL =
1,000,001
RATE OF ADDITION =RATE OF REMOVAL
RATE OF REMOVAL <RATE OF ADDITION
RATE OF REMOVAL >RATE OF ADDITION
Cannot be determined with the information given.
e200
4. Under what conditions would the amount of the thing in the environment
decrease?
RATE OF ADDITION = 1,000,000 and RATE OF REMOVAL = 1,000,001
RATE OF ADDITION =RATE OF REMOVAL
RATE OF REMOVAL <RATE OF ADDITION
RATE OF REMOVAL >RATE OF ADDITION
Cannot be determined with the information given.
ea2oc9
5. Based on this framework, what would have to be done to decrease the amount
of carbon dioxide in the atmosphere?
Based on this framework, carbon emissions would have to be less than
carbon removal for the amount of carbon in the atmosphere to decrease.
17
Systems thinking skills required:
-Recognizing interconnections.
-Understanding stocks and flows.
-Understanding accumulation in the system
18
