What Specific Strategies Enhance Learning?

 

One of the most stimulating insights in contemporary educational theory is Benjamin Bloom's (1984) discussion of solutions to what he calls "the two-sigma problem." Bloom shows that students provided with individual tutors typically perform at a level about two standard deviations (two "sigmas") above where they would perform with ordinary group instruction. This means that a person who would score at the 50th percentile on a standardized test after regular group instruction would score at the 98th percentile if personalized tutoring replaced the group instruction. This improvement is not a wild dream. Bloom supports his claim with valid research, and numerous experts agree with his conclusion.

Bloom proposes the impressive but possibly attainable goal of trying to make group instruction as effective as individual tutoring. Bloom identifies several alterable variables that have been shown to provide a partial "solution" to this two-sigma problem.

Note that this emphasis on the two-sigma problem does not contradict the importance of academic learning time discussed earlier in this chapter. Indeed, the main reason these strategies have such impact is because they promote the effective use of academic learning time.

Table 2.7 lists modifiable factors that Bloom found to be related to enhanced learning. Note that on Bloom's scale a score of 2.0 indicates the level of improvement that would occur under individualized tutoring. This is Bloom's "ideal" score, and other pedagogical strategies can be regarded as effective to the extent that they approach this ideal. For example, when teachers assign homework, there is an average effect size of .30 compared to similar classes in which there is no homework assigned. When teachers not only assign but also grade homework, there is an effect size of .80 compared to similar classes in which homework is not assigned.

 

 

Table 2.7. Selected Alterable Variables That Influence Student Achievement

Effect Size
Percentile*
Strategy
 2.00
98

Tutorial instruction

 1.20
86

Reinforcement

 1.00
84

Corrective feedback

 1.00
84

Cues and explanations

 1.00
84

Student classroom participation

 1.00
84

Student time-on-task

 1.00
84

Improved reading / study skills

.80
79

Cooperative learning

 .80
79

Homework (graded)

 .60
73

 Classroom morale

 .60
73

Initial cognitive prerequisites

 .50
69

Home environment intervention

 .40
66

Peer and cross-age remedial tutoring

 30
 62

Homework (assigned)

 .30
 62

Higher order questions

 .30
 62

New science and math curricula

 .30
62

Teacher expectancy

 .20
58

Peer group influence

 .20
58

Advance organizers

.25
60

Socioeconomic status (Included for contrast - SES is not easily alterable by teachers.)

*The percentile indicates the percentile at which the "average" student would typically score if he/she received this treatment instead of "traditional" instruction. (Ordinarily, the "average" student would score at the 50th percentile.)

(Adapted from Walberg, 1984)

Vockell (1994) has reversed Bloom's logic and has discussed the "minus two-sigma problem." He reasons that if teachers teach really incompetently, they will lower students' performance by an effect size of 2.0. (Having no teacher at all could be perceived as the opposite of having an individual tutor.) He suggests that various activities in which teachers sometimes engage hurt student performance to the extent that they approximate a truly do-nothing teacher. For example, teachers who have students turn quiz papers in so rapidly that they cannot possibly profit from the feedback probably reduce student performance by an effect size of .50. Vockell's main suggestion is that teachers not only need to do things to enhance ALT, they also need to stop doing things that waste ALT.

 

Online Links:

Strategies That Enhance Learning

 

What Helps Students Learn? by Margaret C. Wang, Geneva D. Haertel, and Herbert J. Walberg
http://www.ascd.org/readingroom/edlead/9312/wang.html

An analysis of 50 years of research reveals that direct influences like classroom management affect student learning more than indirect influences such as policies.

 

This entire article from Educational Leadership is online at the ASCD web site:

 

How People Learn: Brain, Mind, Experience, and School. National Research Council. Washington, D.C.: National Academy Press, 1999.
http://www.ascd.org/readingroom/edlead/9911/reviews.html

This is the review of a book in which the authors explore (and extensively document) several major areas of research that have direct application for educational practice: expert performance, transfer of learning, learning in early childhood, the brain and learning, learning environments, effective teaching, and new technologies. This is the second of two reviews in this article, You'll have to scroll down to find it.

 

A Short Quiz on the Two-Sigma Problem

 

  1. Tammy is a student in a traditional class who scored at the fiftieth percentile on a standardized achievement test. According to Bloom's research on the two-sigma problem, at what percentile would Tammy probably have scored if she had received individual tutoring over the same subject matter?

 

a. 50th

b. 52nd

c. 75th

d. 80th

e. 98th

 

Answer: e


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