Feedback
"Meta-Analytic Synthesis of Studies Conducted at Marzano Research Laboratory on Instructional Strategies"
August 2009
(475k PDF)
Feedback involves providing students with information relative to how well they are doing regarding a specific assignment.
The following table presents a summary of findings from two meta-analyses of the experimental/control action research studies in Marzano Research Laboratory's Meta-Analysis Database which utilized this strategy (for a listing of the action research studies, click here). One meta-analysis was conducted using the reported effect sizes from the action research studies in our database. The second meta-analysis (findings reported in parentheses) was conducted using effect sizes that were corrected for attenuation due to a lack of reliability often associated with teacher-designed assessments of student academic achievement (for a discussion of attenuation and meta-analysis and the method used to correct for attenuation click here). Both meta-analyses employed a random-effects model of error (for a discussion of models of error in meta-analysis click here).
| Number of Studies |
Weighted Average Effect Size |
95% CI |
Standard Error |
Minimum Effect Size |
Maximum Effect Size |
Percentile Gain |
| 26 |
0.22
(0.26)
|
[−0.04, 0.48]
([−0.03, 0.55]) |
0.13
(0.15) |
−0.80
(−0.93) |
3.63
(4.19) |
9
(10) |
Consulting a table of the normal curve, the overall percentile gain associated with the corrected weighted average effect size of 0.26 is 0.1026. This suggests that on the average, the use of feedback activities by teachers in the action research studies was associated with a gain in student academic achievement of 10 percentile points over what was expected when teachers did not use feedback activities. In order to illustrate this gain, consider a hypothetical student who is ranked in the middle of a control group with 100 students. Under an assumption that everything else is equal, if this student were the only one to receive instruction with the strategy, his or her ranking would improve from 50th to 40th. In other words, the student would be expected to surpass 60% of the students that did not receive instruction with the strategy.
The effect sizes reported in the table are weighted averages of all the effect sizes from the action research studies and should be considered estimates of the true effect size of the experimental condition (i.e., use of activities that provide students with information relative to how well they are doing regarding a specific assignment). Therefore, the 95% confidence interval (95% CI) is also reported for each effect size estimate. For example, the confidence interval reported in parentheses [−0.03, 0.55] indicates a 95% certainty that the true effect size falls between −0.03 and 0.55. When the confidence interval does not include 0.00, the weighted average effect size can be considered statistically significant. In other words, an effect size of 0.00 would not be considered a reasonable assumption.
These findings are low in comparison with other meta-analytic studies related to feedback (range: 0.26 to 1.47).
Related Research
Meta-Analytic Studies on Feedback