Low-Cost Instructional Changes Can Cut Achievement Gap in Intro Biology, Scholars Say

June 02, 2011

When instructors at the University of Washington redesigned their introductory-biology course in a "highly structured" style, with active-learning exercises, daily quizzes, and weekly online essay assignments, all students' performance improved, but especially the performance of students whose high-school preparation was weak. The achievement gap between students from advantaged and disadvantaged backgrounds closed by nearly half.

And all of that, the instructors believe, can be accomplished at any college without increasing instructional costs. In fact, they achieved their gains during a period when budget pressures at Washington forced a doubling of the course's maximum size, from 345 to 700.

The scholars report their findings in the June 3 issue of Science. (The paper is accessible only to subscribers.)

"Simple changes in teaching style can dramatically improve students' performance across the board," said David C. Haak, one of the paper's four authors, in an interview on Wednesday. Mr. Haak earned a doctorate in biology at Washington in 2010 and is now a postdoctoral researcher at Indiana University at Bloomington.

The course's redesign was led by Scott Freeman, a lecturer in biology at Washington who is also among the paper's authors. According to Mr. Haak, the Washington team borrowed liberally from pedagogical reforms in physics. In a related paper published this year in CBE Life Sciences Education, Mr. Freeman and two colleagues describe the basic elements of the redesigned course:

  • Instead of simply lecturing, the instructors frequently call on students to answer questions. After the class size increased to 700, Mr. Freeman developed a method of randomly calling on a certain number of students each day.
  • During class time, the students are asked to do short ungraded assignments. Those include "minute papers" (papers that summarize the day's main idea, are expected to be written in 60 seconds, and must conclude with a question about something that puzzles the student) and case studies reviewed in small groups.
  • Each week outside of class, students are required to answer five short-answer questions. The answers are then randomly and anonymously given to other students in the class for grading. Students are also required to answer multiple-choice questions about the reading for the next week's lecture.

In the Science paper, Mr. Freeman and his colleagues compare students' performance in two highly structured sections of the course with other students' performance in 27 less-structured sections in recent years. In the highly structured sections, the instructors write, the raw achievement gap between disadvantaged students and their peers was 0.44 grade points—much better than the 0.8-point gap in the other sections.

The Washington instructors did make a sacrifice, however. When the class size ballooned, they reduced the number of weekly laboratory hours from three to two. Mr. Haak says that was a painful choice, but it was the only way to preserve teaching assistants' time for grading essays. The instructors did not want to turn to a multiple-choice test format because they were committed to helping students learn high-level problem-solving and analysis, not simple memorization of facts.

"It was tough," Mr. Haak says. "The real crux was finding a way to maintain the number of essay questions, without having the TA's go stir-crazy trying to grade them all." (One answer was to have more-frequent but smaller tests.)

Mr. Freeman and Mr. Haak were joined in writing the paper for Science by Janneke Hille Ris Lambers, an assistant professor of biology at Washington, and Emile Pitre, associate vice president for minority affairs at the university.

Mr. Haak and his colleagues are now applying for grants to support training programs that might spread the model to other campuses. They also plan to analyze further data from the Washington campus, including statistics about how well students perform in subsequent biology classes after taking the redesigned introductory course.