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Issue-Based Teaching in Science Education

Susan E. Lewis


Using issues in the science classroom helps students to:

  • develop the skills of critical analysis and life-long learning
  • deal with the changing nature of science in society
  • make decisions about the scientific issues they will face in the future
  • make science “come alive”

September 2003

Scientific issues in the media challenge us almost daily.

A wide variety of science-based issues for teaching can be found in a newspaper. Photo: Microsoft Image.

  • “Anthrax vaccine: Controversy over safety and efficacy”
  • “Shanghai issues new SARS regulation”
  • “US to withdraw from Kyoto Global Warming Treaty”
  • “Is the Endangered Species Act in danger?”
  • “Brain disease rises in deer, scaring hunters”
  • “UK to approve ‘therapeutic cloning’”
  • “Born-again Quagga defies extinction”
  • “President Bush and environmentalists disagree on forest fire policy”
Tackling issues makes science “come alive.”

One needs only to open a newspaper to identify a wide variety of science-based issues that can serve as an excellent vehicle for making science “come alive” for students. Using issues in the classroom also allows an instructor to foster the students’ skills of critical analysis and life-long learning that they need to deal with the changing nature of science in society. Providing students with the tools necessary to critically evaluate and make decisions about the future scientific issues they will face is central to scientific literacy education.

First case study: reformulated gasoline issue

An issue that affects our daily life makes an interesting scientific debate.

In an introductory course in Environmental Science for undergraduate students (primarily for non-science majors) in our College Honors program, I posed the question:

“Should the Environmental Protection Agency have waived the reformulated gasoline requirement for Milwaukee [Wisconsin] in the summer of 2000?”

Reformulated gasoline (RFG) has oxygenating additives such as ethanol or MTBE that, at least in theory, decrease harmful emissions of ozone and ozone precursors (e.g., carbon monoxide, nitrogen oxides). Cities with ground-level ozone levels in excess of acceptable levels are mandated by the EPA to use RFG. In the summer of 2000, gasoline prices soared to over $2.00 per gallon, with the increase largely attributed to the RFG requirement. In response, several local governments sued the EPA to waive the requirement due to the wide-spread economic impact resulting from the increased fuel costs, combined with questions about the effectiveness of RFG.

The issue was chosen for four primary reasons:

  • The course was taught in the fall of 2000, so the issue was very current and relevant in the minds of the students. They felt a direct stake in the issue every time they put gas in their car.
A scientific issue can have political, economic, and social ramifications.
  • The issue involved a great deal of science. Students needed to understand what gasoline is and how it is made, the basic chemistry of combustion, the by-products of combustion, the biological implications of air pollution, etc. As with many scientific issues, the issue also involved a level of uncertainty that students had to deal with.

  • The issue had political, economic, and social ramifications. Students recognized a key ramification when they saw gas prices soar to over $2.00 per gallon, but also came to learn about how political decisions are made and the relationship between scientific evidence and public policy.

  • The issue had no clear answer. This helps students to understand that there isn’t always a “right” answer, and reinforces the importance of making informed decisions that are well-supported by evidence.

The unit was structured to emphasize student-led investigation. Students developed a list of what they felt they needed to understand in order to answer the question posed and brainstormed potential sources of that information. Class sessions included lectures, guest speakers, field trips, group presentations, and class discussions. Groups of students were responsible for researching topics such as:

One issue can involve a variety of topics.
  • air quality regulations
  • ethanol and MBTE
  • the supply and distribution of reformulated gas
  • the economics of reformulated gas

and then making presentations to the class as a whole. Class sessions were supplemented by readings from the National Academy of Sciences’ report on reformulated gasoline and readings from a general environmental science textbook. Laboratory sessions during this unit investigated the effects of ground-level ozone on milkweed leaves (Asclepias syriaca), which gave students an opportunity to experience the process of scientific investigation and why uncertainty is a part of all scientific endeavor.

Learning focuses not only on scientific concepts, but also on critical thinking and decision making skills.

I assessed student learning by evaluating:

  • class presentations
  • participation in discussions
  • laboratory reports
  • final papers in which they presented their “decision” on whether the EPA should have waived the reformulated gas requirement
  • a written examination on the scientific concepts introduced in the unit
When analyzing an issue, students are forced to struggle with ambiguity, uncertainty, and incomplete data.

It is worth noting that my own background with respect to this issue was minimal, so I was learning with the students. This was advantageous in that I could model the value of life-long learning and I could clearly empathize with their struggle to come to grips with the ambiguity of the issue. On the other hand, students would certainly have traded my empathy for more guidance as they wrestled with what was a very difficult issue.

  • The “reformulated gasoline” unit pushed students to critically analyze a contemporary environmental issue.
  • In doing so, they had to learn a variety of scientific concepts and also how science is done.
  • Most vividly, they wrestled with the role of uncertainty in science and how that uncertainty comes to play at the interface between science and public policy.

This was a difficult and frustrating unit for many of the non-science majors. Yet student evaluations and my own impressions suggested that despite the frustration, many students found value in the experience and came to appreciate that often policy decisions need to be made when supporting data are incomplete or there is not time for more research.

Perhaps most importantly, focusing on a current issue allowed the students to work through the type of process they’ll need to undertake when they are trying to analyze an issue they read in the newspaper someday, but to do so with a variety of academic support structures in place.

Second case study: zoology issues

Delegating students to be “experts” on a given topic promotes research on all sides of an issue.

To help students (primarily science majors) in a vertebrate zoology course build skills in finding and evaluating evidence and allow them to build connections between course material and the “real world,” I assigned a series of issue discussions throughout the one-semester course. Students selected three issues during the semester about which they would become the “experts.” Experts were responsible for researching the evidence on all sides of the issue, preparing a summary statement that explained the issue, using evidence to support a particular position on the issue, and, working with other experts, facilitating a class discussion on the issue.

The course was organized in units that focused on each major vertebrate class, and I assigned one issue in each unit. This constraint sometimes made it challenging to identify a strong issue about which there was true disagreement. Sample issues selected for the course included:

An issue can be matched with a unit of study.
  • “Aquatic exotics — what’s the fuss?” which focused on the problems with defining and assessing the impact of introduced fish species.
  • “Are birds really feathered dinosaurs?” which assessed recent evidence on the origin of birds.
  • “Don’t shoot Bambi — shoot his mom!” which looked at the strengths and weaknesses of various white-tailed deer herd management practices.
Assessment criteria include research and critical thinking skills, as well as discussion quality.

In their written and oral presentations, evidence of the following criteria was assessed:

  • rigorous research
  • a clear understanding of the issue and of the sources used
  • critical thinking
  • preparation and ability to teach classmates about the issue
  • a logical structure to the paper and discussion

All of the students in the course agreed that the issue discussions were a valuable part of the class that helped them achieve the course objective of being able to “locate, synthesize, and discuss semi-technical scientific information about current issues in vertebrate zoology.” The most common criticism of the issue discussions was that the “experts” tended to focus more heavily on presentation, rather than discussion of the material.

Issues have no clearly-defined single outcome or answer.

What makes a good issue?

Issues can be framed as case studies or problems.

An issue is basically defined as a topic with no clearly-defined single outcome or answer — something about which reasonable people might be expected to disagree. Issues can also be framed in terms of a case study, particularly those known as “decision cases” or “dilemma cases,” or a problem, as in problem-based learning. Issues most useful for teaching science are characterized as “data-rich,” so students have an opportunity to consider and evaluate potentially contradictory evidence, as well as to understand how that evidence was generated. Often, data sets can be extracted from published literature, to allow students to work through the same decision-making strategies as the original researchers. Issues should also make clear connections to the course objectives with respect to both content and skills, and instructors should work to reinforce and support these connections through all phases of the educational process.

Contemporary issue advantage: often best captures student interest.
Historical issue advantage: can see how issue was actually resolved.

Although issues with contemporary relevance often best capture student interest, some historical issues provide useful educational opportunities as well. For example, the American Biology Teacher published an article entitled, “The Tragedy & Triumph of Minamata: The Paradigm for Understanding Ecological, Human-Environment & Culture-Technology Interactions.” Minamata disease is a neurological disorder caused by methylmercury poisoning, resulting from industrial waste being dumped into a marine system where there was an active fishing industry. Students could investigate a variety of biological (as well as social, political, and legal) concerns connected with this issue. Given the historical nature of this Japanese disaster in the 1950s and 1960s, students would also be able to see how the issues raised were actually resolved, one of the things that is difficult to do with contemporary issues.

Other excellent historical issues include:

  • the recombinant DNA controversy of the late 1960s
  • the regulation of clorofluorocarbons in the 1970s and 1980s
  • the response of deer populations on the Kaibab plateau in Arizona, following the removal of major predators
  • the attempt of Biosphere 2 to serve as a model of the Earth’s environment
  • dinosaur extinctions and the significance of Mexico’s Chicxulub crater
  • the spotted owl debate in the Pacific Northwest

The issues used in a science course can be simple or complex, depending on the goals of the course. The issue might be addressed in a single class session, over the course of several class sessions, for an entire unit, or even for an entire course. Issues can be taught with a heavy reliance on lecture/discussion or with the focus on independent or collaborative inquiry.

Reflections on teaching and learning with issues

Scientific literacy should encompass real world problems and issues.

In 1996, the National Research Council outlined key objectives for science literacy at the undergraduate level, indicating that students should:

  • understand the basic principles used to explain natural phenomena
  • connect science, mathematics, engineering, and technology to real world problems and issues
  • understand the processes by which scientists, mathematicians, and engineers investigate and solve problems
  • be exposed to information that is broad and current
  • acquire the ability to remain life-long learners about these subjects2
Issue-based education connects scientific evidence to social and political perspectives.

This level of scientific literacy is seen as critical both for encouraging interested and talented students to pursue careers in science and for educating a citizenry prepared to critically evaluate and respond to the changing needs of society in an increasingly-technological future. “Science, mathematics, and technology are defined as much by what they do and how they do it as they are by the results they achieve.”3 Given this, providing students with a strong understanding of science entails more than providing them with a body of content. We need to encourage students to ask and answer their own questions, to evaluate and use evidence, to relate historical perspectives to current conditions, and to connect scientific evidence to social and political perspectives.3 Issue-based education provides an excellent vehicle for achieving these goals.

To incorporate issues, teachers may need to restructure their methodology.

Incorporating issues into a course requires rethinking many aspects of the teaching and learning process.

  • Preparation: Instructors need to search diverse media sources — including journals, magazines, the Internet, and newspapers for appropriate issues. Instructors can also take advantage of an increasing number of resources now available with prepared issues in the form of case studies or problem-based learning activities (see “learn more” links at end of this article).

  • Developing skills: Issue-based education should build students’ core skills in:

    • reading critically
    • identifying important information and discriminating fact versus opinion
    • identifying what is know and what is unknown
    • locating and evaluating sources of evidence
    • understanding scientific method and recognizing weaknesses in the design of scientific research (e.g., lack of replication, inadequate controls)
    • framing data-rich arguments (e.g., using graphs effectively)

Instructors should intentionally build these skills by modeling the process they wish students to follow, or having students work on issues of increasing complexity as their skills improve.

  • Leading the discussion: Student’s need a “road map” for how to find the information that they need to engage in the case; this changes the instructor’s role from one of gathering and disseminating the material directly. Students who feel uncomfortable with analyzing challenging data and evidence in a science-based case might tend to focus more on the social/political aspects of the issue, so instructors should be prepared to guide and direct students to achieve the objectives of the exercise. Instructors should also be prepared to relinquish a greater level of control in the classroom to give the students the freedom to wrestle with the issue in their own way.
Students must make a decision and are evaluated on the quality of their analysis.
  • Assessing the outcomes: It is critical that instructors develop assessments directly connected to the objectives of the experience, which strengthens student motivation to acquire the essential analytical skills of the exercise. Structuring a formal outcome where students must make a decision and support it helps students to find closure on the issue, even if there is not a satisfactory “right answer.” At the same time, a well-defined grading rubric helps students understand that they are being evaluated on the quality of their analysis, rather than on whether they agree with the instructor’s views or not.
Conclusion: Issue-based teaching promotes scientific literacy and higher-order thinking skills.

Educators in science often feel compelled to concentrate on the conveyance of vocabulary, facts, and concepts. As a result, they may rely fairly heavily on the lecture method of presentation. However, if we are truly committed to the objectives of science literacy, we need to also incorporate strategies to teach higher-order thinking skills. Issue-based education can serve that need. Dr. C. F. Herreid, Director of the Center for Case Study Education in Science at the State University of New York, Buffalo, notes that issue-based case studies in science:

“… involve learning by doing, the development of analytical and decision-making skills, the internalization of learning, learning how to grapple with messy real-life problems, the development of skills in oral communications, and often team work. It’s a rehearsal for life.”1

Susan E. Lewis, Ph.D., is Associate Professor and Chair of Biology and Director of Faculty Development at Carroll College in Waukesha, Wisconsin. She teaches courses in Animal Behavior, Ecology and Evolution, Environmental Science, and Vertebrate Zoology. In addition, Dr. Lewis was involved in Project Kaleidoscope (PKAL), an informal national alliance of individuals, institutions, and organizations committed to strengthening undergraduate science, mathematics, engineering, and technology education. Dr. Lewis received her Ph.D. in Behavioral Ecology from University of Minnesota.

Issue-Based Teaching in Science Education and issue-based teaching promotes bioscience literacy and issue-based teaching through its articles and accompanying class lessons. You are encouraged to look through the variety of educator resources presented on our web site. In addition, the following original article is on a related topic: “Tapping into the pulse of the history of science with case studies” by Douglas Allchin, Ph.D., at

Other resources for issue-based teaching in the biological sciences

Evaluating Internet information

Web site evaluation is important when deciding whether a site’s information comes from a respected source and if it is suitable and relevant for use as research information on an issue. Some resources for site evaluations:

Resources on reformulated gasoline (first case study in article)

Resources on Minamata disease (discussed in article)

The Web-based Inquiry Science Environment (WISE)

“Students learn about and respond to contemporary scientific controversies through designing, debating, and critiquing solutions.”

Internet research note-taking tool

Using NoteStar, students can take notes from online sources as they browse the Internet for issues and other information. “Source information (i.e., title, URL, etc.) is automatically captured in order to assist in work citation.” Also, “teachers can track each student’s progress.”

Developing issue-based teaching in your classroom

The links in the “learn more” section above provide information for developing issue-based teaching in your own classroom. is very interested in hearing about your success stories with issue-based teaching. Contact

Project Kaleidoscope (PKAL)

Sharing of ideas and resources is available through this multi-faceted organization which “focuses on building learning environments that attract undergraduate students to the study of science, technology, engineering and mathematics.”


Teaching Resources from the Northwest Association for Biomedical Research (NWABR)

The Northwest Association for Biomedical Research (NWABR) strengthens public trust in research through education and dialogue. Its diverse membership spans academic, industry, non-profit research institutes, health care, and voluntary health organizations. Through membership and extensive education programs, it fosters a shared commitment to the ethical conduct of research and ensures the vitality of the life sciences community.

NWABR Research Study on Bioethics Education
Fostering Critical Thinking, Reasoning, and Argumentation Skills through Bioethics Education –results show that when students learn strategies for ethical reasoning, they grow significantly in their ability to develop strong arguments for their positions.

  1. Herreid, C. F. 1994. “Case studies in science: A novel method of science education.” Journal of College Science Teaching 23:221-229.
  2. NRC 1996. “From analysis to action: Undergraduate education in science, mathematics, engineering, and technology.” National Research Council. National Academy Press (Washington, D.C.).
  3. Project 2061. 1990. Science for All Americans. American Association for the Advancement of Science. Oxford University Press (New York, Oxford).


Understanding Science