Postdocs Can Be Trained to Be More Effective Than Senior Instructors, Study Finds

May 12, 2011

Trained but inexperienced postdoctoral students can teach a college class as well as or better than longtime professors who rely on lectures, if the postdocs learn to incorporate a method of teaching that relies on having students interact with the material they are learning through discussions and assignments synthesizing new and old information and experiences, according to a paper published this week in Science.

"When there is a good, traditional lecture, the student reviews are high, but when you measure the learning, it is surprising how little is learned," said Louis Deslauriers, a research associate in the department of physics and astronomy at the University of British Columbia and one of the lead authors of the paper, "Improved Learning in a Large-Enrollment Physics Class."

Mr. Deslauriers and his co-authors—Carl E. Wieman, associate director of science at the White House Office of Science and Technology Policy, and Ellen Schelew, a graduate student in the department of physics and astronomy at British Columbia—write in the paper that an inexperienced instructor with the proper training can increase student engagement, raise attendance, and create an environment that is conducive to learning.

The researchers looked at two sections of an undergraduate introductory-physics course, with a control group to be "lectured by a motivated faculty member with high student evaluations and many years of experience teaching this course" and the experimental group to be "taught by a postdoctoral fellow using instruction based on research on learning."

The experimental group was taught by Mr. Deslauriers and Ms. Schelew, neither of whom had much experience teaching introductory physics. Neither had worked with this particular group of students before either.

For one week, the control group, with 267 students, and the experimental group, with 272 students, met three times, covering the same learning objectives in one-hour sessions.

Before beginning the experiment, the researchers observed lecture-based classes and found that such a style of teaching did not seem to give students time to synthesize and incorporate new ideas from the lecture into their prior knowledge and experiences. "The information just keeps following in the lecture," Mr. Deslauriers said.

In an effort to improve learning in the class, the teachers in the experimental group relied on a method called "deliberate practice," which combines the ideas in what's known as formative assessment and constructivism. Formative assessment uses various practices, such as pretests, to provide teachers with information about what students already know and how they learn. Constructivism stresses the interaction of students with the information they are learning and their day-to-day lives. The teachers incorporated that approach by adding "a series of challenging questions and tasks that require the students to practice physicist-like reasoning and problem solving during class time while provided with frequent feedback."

"Deliberate practice helps you understand why some practices work and how they can be optimized," said Mr. Wieman, who shared the 2001 Nobel Prize in Physics.

The experimental group saw higher attendance and student engagement during the course. Mr. Deslauriers said the jump was not caused by the novelty of a weeklong interruption from traditional lectures but stemmed from the methods used in the experimental group, which engaged students in a way that made them want to attend class.

In a survey conducted at the end of the week, 90 percent of students agreed or strongly agreed that they "really enjoyed" the work in the experimental group and 77 percent agreed that they would have learned more if the entirety of the course were taught using those methods.

The students' belief that they had learned more held true in a quantitative measure. On a test given at the end of the week, the students in the experimental group did more than twice as well as the students in the control group.

Mr. Deslauriers cautioned that instructors who wanted to change methods to improve learning in their classrooms would have to spend a fair amount of studying the practices for them to be effectively executed.