Preventing symptoms of depression by teaching adolescents that people can change: Effects of a brief incremental theory of personality intervention at 9-month follow-up
Miu, A. S., & Yeager, D. S. (2014). Clinical Psychological Science, 3(5).
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examining599Students, grade9
Single Study Review
Review Details
Reviewed: November 2025
- Single Study Review (findings for Incremental theory of personality intervention - Miu & Yeager (2014))
- Randomized Controlled Trial
- Meets WWC standards without reservations because it is a randomized controlled trial with low attrition.
This review may not reflect the full body of research evidence for this intervention.
Evidence Tier rating based solely on this study. This intervention may achieve a higher tier when combined with the full body of evidence.
Findings
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Outcome measure |
Comparison | Period | Sample |
Intervention mean |
Comparison mean |
Significant? |
Improvement index |
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|---|---|---|---|---|---|---|---|---|---|
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Children's Depression Inventory short form (CDI:S) |
Incremental theory of personality intervention - Miu & Yeager (2014) vs. Intervention |
9 Months |
Full sample;
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2.89 |
3.44 |
No |
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| Show Supplemental Findings | |||||||||
|
Children’s Depression Inventory |
Incremental theory of personality intervention - Miu & Yeager (2014) vs. Intervention |
9 Months |
Full sample;
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16.00 |
25.00 |
Yes |
|
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Evidence Tier rating based solely on this study. This intervention may achieve a higher tier when combined with the full body of evidence.
Sample Characteristics
Characteristics of study sample as reported by study author.
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Female: 48%
Male: 52% -
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California
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Race Other or unknown 50% White 50% -
Ethnicity Other or unknown 100% -
Eligible for Free and Reduced Price Lunch Other or unknown 100%
Study Details
Setting
This study was conducted in three northern California high schools. Two schools were upper-middle class and high performing. The third school was among the lowest performing and served the lowest income population in the San Francisco Bay area. In two of the high schools, students completed the brief intervention in their Algebra class. In the third school, all 9th grade students participated in the study, regardless of math placement.
Study sample
Students were included from three different schools in Northern California. Demographic characteristics are provided at the school level. Across all schools, 48% of students were females and 52% were males. Two schools had about 51% White and 46% Asian American students and only 6% were eligible for free or reduced-price lunch. In contrast in the third school, 80% of students reported being Hispanic/Latino and 73% were eligible for free or reduced-price lunch. Except for percent female and percent White, the study did not provide aggregated measures of ethnicity or race across all three samples.
Intervention Group
The experimental intervention was administered by researchers during one class period. The activity focused on the malleability of personal traits and included three parts: 1) reading a scientific article on people's potential for change, 2) reading testimonials from upperclassmen, and 3) writing a narrative for incoming freshmen that endorsed the ideas of the article and were based on personal experiences. The intervention took about 25 minutes to complete on average.
Comparison Group
Students in the comparison condition performed similar activities, except that the messages in the materials they read focused on the malleability of athletic ability.
Support for implementation
Research assistants administered the interventions. The only requirements of teachers or research assistants was to keep the class quiet while administering the study sessions.
An indicator of the effect of the intervention, the improvement index can be interpreted as the expected change in percentile rank for an average comparison group student if that student had received the intervention.
For more, please see the WWC Glossary entry for improvement index.
An outcome is the knowledge, skills, and attitudes that are attained as a result of an activity. An outcome measures is an instrument, device, or method that provides data on the outcome.
A finding that is included in the effectiveness rating. Excluded findings may include subgroups and subscales.
The sample on which the analysis was conducted.
The group to which the intervention group is compared, which may include a different intervention, business as usual, or no services.
The timing of the post-intervention outcome measure.
The number of students included in the analysis.
The mean score of students in the intervention group.
The mean score of students in the comparison group.
The WWC considers a finding to be statistically significant if the likelihood that the finding is due to chance alone, rather than a real difference, is less than five percent.
The WWC reviews studies for WWC products, Department of Education grant competitions, and IES performance measures.
The name and version of the document used to guide the review of the study.
The version of the WWC design standards used to guide the review of the study.
The result of the WWC assessment of the study. The rating is based on the strength of evidence of the effectiveness of the intervention. Studies are given a rating of Meets WWC Design Standards without Reservations, Meets WWC Design Standards with Reservations, or >Does Not Meet WWC Design Standards.
A related publication that was reviewed alongside the main study of interest.
Study findings for this report.
Based on the direction, magnitude, statistical significance, and sample size of the findings within a domain, the WWC assigns effectiveness ratings as one of the following: Tier 1 (strong evidence), Tier 2 (moderate evidence), Tier 3 (promising evidence), uncertain effects, and negative effects. For more detail, please see the WWC Handbook.
The WWC may review studies for multiple purposes, including different reports and re-reviews using updated standards. Each WWC review of this study is listed in the dropdown. Details on any review may be accessed by making a selection from the drop down list.
Tier 1 Strong indicates strong evidence of effectiveness,
Tier 2 Moderate indicates moderate evidence of effectiveness, and
Tier 3 Promising indicates promising evidence of effectiveness,
as defined in the
non-regulatory guidance for ESSA
and the regulations for ED discretionary grants (EDGAR Part 77).