Think-Pair-Share Activity for Understanding Price Controls

This page authored by Linda K. Carter, Baylor University
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This material is replicated on a number of sites as part of the SERC Pedagogic Service Project


In a think-pair-share activity, students first work independently to demonstrate mathematically and graphically how price floors and ceilings affect market outcomes. Students are then paired to share and revise their answers before being randomly chosen to report answers to the larger class.

  • This exercise is designed for a principles of microeconomics course; however, instructors reviewing price controls in any course might find them equally useful.
  • Follow up exercises are provided so that instructors might engage students with additional problem solving outside of class or develop additional think-pair-share exercises on these and related supply and demand concepts.

Learning Goals

Use equations for supply and demand to mathematically solve for equilibrium, calculate consumer and producer surplus, and demonstrate the market outcome graphically (Proficiency: accessing existing knowledge).

Analyze the predicted impact of price floors and price ceilings on market outcomes, such as quantity traded, consumer/producer surplus, and efficiency (Proficiency: displaying command of existing knowledge).

Follow up exercises are provided which reinforce the mathematical/graphical examination of price controls and compare the impacts of price controls to an alternative policy mechanism (increasing supply).

Context for Use

Knowledge required: This exercise is intended to be administered after a standard chapter on price controls is covered mathematically/graphically by the instructor.

Class size: This exercise was originally designed for a class of 35-40 students, but it can be easily adapted for smaller or larger classes.

Timing: The exercise is designed to take a total of 20 minutes.

Description and Teaching Materials

Two handouts are provided to support this exercise. The Student Handout for Price Controls Exercise (Microsoft Word 2007 (.docx) 19kB Apr29 12) includes instructions for the think-pair-share exercise. Answer Key for Price Controls Exercise (Microsoft Word 2007 (.docx) 49kB Mar27 12) is a detailed answer key for the exercise.


Teaching Notes and Tips


Class size poses no constraints on utilizing this exercise as it only requires that instructors facilitate the pairing of students after the initial independent work is completed.

The 20-minute exercise is comprised of the following think-pair-share components: 8-10 minutes for students to work independently to solve the problem, 5-7 minutes to share and revise answers, and 5 minutes for reporting back to the larger class.


As part of the set-up for this exercise, students are told to treat it as if it were an exam question in order to test their comprehension. Students are encouraged to attempt the exercise during the think stage of the exercise without looking at their notes and to provide a carefully constructed (and labeled) answer. Requiring students to independently formulate a draft answer in this stage ensures individual accountability.

Student pairs are the mechanism by which positive interdependence is facilitated. In this exercise, since two students are working together towards a single answer, it supports positive interdependence through output goal interdependence.

During the sharing stage of the exercise, students methodically take turns presenting their answers to different parts of the exercise (see instructions on exercise handout) as their partner reflects and asks questions of clarification through face-to-face (promotive) interaction. This also supports positive interdependence by explicitly generating role interdependence.

During the thinking and sharing stages of the exercise, it is imperative that the instructor move throughout the classroom to check in with students, monitoring progress, and intervening when necessary. Although instructors may be tempted to directly answer student questions during this period of time, student learning is enhanced to a greater degree if the instructor guides struggling students by posing reflective questions back to them.

Conclusion to exercise:

Reporting back to the larger group can be facilitated by tossing a soft ball to a random pair and asking them to share part of their answer. Thereafter, students toss the ball to another pair to share a remaining part of the exercise. This process continues until all parts of the answer have been covered. When students are sharing parts of the answer that involve a graphical component, the instructor may wish to ask them to draw the graph on the blackboard.

Alerting students in advance that some pairs will be randomly called upon to explain their answers to the class at the close of the exercise helps to motivate students to work diligently on the task during class and - because the reporting out process occurs in this manner (via a somewhat random draw of students) - students are more engaged in the process.

Further considerations:

Since the exercise requires students to work with equations, some students may encounter difficulties starting the problem. If this is likely to be an issue, frustration could be minimized by requiring students to present solutions to a practice problem solving two equations for two unknowns (and graphing the lines) as an "admission ticket" to class on the day of the exercise. Submitting this admission ticket gives a student the right to work together with another student who has also completed the practice problem. Although calculators should not be necessary for solving these problems, instructors may want to encourage students to bring calculators to (or provide them for use in) class if they expect students to feel more confident having a calculator available.


Since students are receiving feedback regarding their understanding during the sharing stages (in pairs and across the larger group), they are participating in formative assessment.

This particular think-pair-share exercise has no formal summative assessment directly tied to it. However, it is set up in a manner that mimics question content and structure which appears on quizzes and exams covering this material. Exercise answer keys are provided to students directly after the exercise (either through handouts or electronic facilitation) to reinforce the learning process.

References and Resources