The Prediction Step

Initial Publication Date: April 27, 2010
A key feature of Interactive Lecture Demonstrations is the requirement that students predict the outcome before they begin an activity.

Why it matters

Research on in-class demonstrations shows that "students who predict the demonstration outcome before seeing it display significantly greater understanding." (Crouch 2004) For descriptions of the prediction step to create a "time for telling" in a variety of disciplines see Derek Bruff, Teaching with Classroom Response Systems

Students are more engaged

  • Begin the lesson with a story based on real-life experience, but stop before the end, asking students "what will happen if..."
  • Show the demonstration in front of the classroom, stopping before the end, asking students what will happen next.
  • Describe a real-life problem for which an answer is needed that will be provided by the upcoming demonstration.

Students connect their in-class work with prior experiences

  • In addition to the prediction, ask students if they have seen similar demonstrations. What happened? Why?
  • Or, ask students if they have studied similar problems. What were the answers? Why?

Students are required to document their prior thinking explicitly

  • Make certain that students put their prediction in writing with a brief explanation why.
  • Ask students to share their prediction and explanation with other students. By doing so, students often will be more articulate about their prior understanding and they will be able to hear other student viewpoints. Learn more about group work

Techniques for student predictions

  • Encourage students to be as specific as possible about their prediction by requiring them to make a choice from possible answers. For example: Instead of predicting whether the target variable will increase or decrease, ask students to choose from a range of percentages or other numerical answers. Also ask students to explain their choices in writing.

  • Require students to choose from a selection of graphs the one that best represents their predictions. For example, students can choose between a linear, exponential, or cyclical function. Choosing a graph helps students think in a more expert manner, gaining practice with choice of variables to be studied, the choice of variables to hold constant, and their representation in a graphical form. Also, choosing among several graphs can challenge students at various skill levels. For some students, selecting between a positive and negative relationship will be a learning experience. For others, who know that, say, the relationship is positive, the choice can be between a linear and non-linear function. For an examples of prediction graphs see Predicting GDP growth (Microsoft Word 28kB Oct10 09).
  • Interactive Lecture Demonstrations sometimes require students to complete two separate pages, one with their prediction, and one with their thinking after the demonstration. However, Redish and Hammer 2009 advocate the use of single page in order NOT to "send students the message that that their intuitions about the physical world are generally misleading and irrelevant to the physics class." They prefer for students to refine their intuitive knowledge rather than set it aside.