Incremental Learning of Difficult Words in Story Contexts: The Role of Spelling and Pronouncing New Vocabulary
Vadasy, Patricia F.; Sanders, Elizabeth A. (2015). Reading and Writing: An Interdisciplinary Journal, v28 n3 p371-394. Retrieved from: https://eric.ed.gov/?id=EJ1051576
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examining69Students, gradeK
Single Study Review
Review Details
Reviewed: November 2025
- Single Study Review (findings for Definitions-Plus - Vadasy & Sanders (2015))
- Randomized Controlled Trial
- Meets WWC standards with reservations because at least one supplemental finding is rated meets WWC standards without reservations but the study does not have main findings.
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
|
Outcome measure |
Comparison | Period | Sample |
Intervention mean |
Comparison mean |
Significant? |
Improvement index |
||
|---|---|---|---|---|---|---|---|---|---|
| Show Supplemental Findings | |||||||||
|
Researcher-designed spelling measure |
Definitions-Plus - Vadasy & Sanders (2015) vs. Other intervention |
1 Week |
Full sample;
|
26.26 |
23.14 |
No |
-- | ||
|
Researcher-designed spelling measure - distractor words |
Definitions-Plus - Vadasy & Sanders (2015) vs. Other intervention |
1 Week |
Full sample;
|
26.68 |
24.82 |
No |
-- | ||
|
Outcome measure |
Comparison | Period | Sample |
Intervention mean |
Comparison mean |
Significant? |
Improvement index |
||
|---|---|---|---|---|---|---|---|---|---|
| Show Supplemental Findings | |||||||||
|
Researcher-designed vocabulary definitions measure |
Definitions-Plus - Vadasy & Sanders (2015) vs. Other intervention |
1 Week |
Full sample;
|
5.70 |
2.86 |
No |
-- | ||
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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100% English language learners -
Female: 42%
Male: 58% -
Race Other or unknown 100% -
Ethnicity Other or unknown 100% -
Eligible for Free and Reduced Price Lunch Other or unknown 100%
Study Details
Setting
This experiment was conducted among kindergarten English Learners with low vocabulary knowledge in 23 classrooms in nine schools in a large US school district. Participants were drawn from an earlier efficacy study (Vadasy, Sanders, and Nelson, 2014).
Study sample
Seventy-two students were randomly assigned to an intervention group with 36 students and a comparison group with 36 students. The analytic sample included 69 students, with 35 in the Definitions-Only (comparison) group and 34 in the Definitions-Plus (intervention) group. Among students in the analytic sample, 42 percent were female, 97 percent received English learner services and 1 percent received special education services. All students were English learners, meaning they spoke a language other than English at home. The most common language spoken at home was an African language (35%), followed by Spanish (29%), Chinese (14%), and Vietnamese (12%).
Intervention Group
The Definitions-Plus intervention was delivered individually every day for six consecutive school days by an experienced reading tutor drawn from the local community (there were seven reading tutors). Sessions were 5-10 minutes and took place outside the student's classroom during the school day. During sessions, the tutor read a story aloud (a different story each day). Each story contained eight target words, repeated three times each in random order, for the students to learn, and the set of eight target words was repeated across three stories (so there were 16 target words total, each of which appeared in three stories, for nine exposures per word). Target words were chosen to be at a higher difficulty level than typical 6-7 year olds have previously encountered. The first time the target word appeared in a story, the tutor provided the definition of the word and then showed the student a card with the target word printed on it. The tutor read the student the word, asked the student to say it aloud, spell it, and say it aloud again.
Comparison Group
The Definitions-Only comparison intervention was identical to the intervention condition except that, when the target word was read for the first time, students were only provided with the definition (no word card or pronunciation practice).
Support for implementation
Seven reading tutors from the local school community were trained to implement the intervention. Each tutor had at least two years of prior experience. Each tutor was individually trained by the first author to use both the Definitions-Only and the Definitions-Plus procedures the week before the intervention was implemented. Tutors were instructed to follow the procedures carefully, depending upon which condition the student was assigned to, and tutors completed a form to record completion of each story and condition.
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).