The study took place in a half-day, state-funded preschool program.
The study began with 43 three- to four-year-old low-income children. During the course of the study, four children moved, one child was excluded because of a high level of
missing data, and five children were excluded because English was their primary language. The final sample included 33 Hmong- or Spanish-speaking children. The children
ranged in age from 42 to 58 months (mean age = 52.8 months), and 64% were female. The children were blocked by primary language and randomly assigned across morning and afternoon classrooms to either the intervention or comparison conditions.
The WWC designated the letter-rhyme group as the intervention condition for this review. The children in this group participated in a total of 48 lessons lasting 20–25 minutes
each (three lessons a week for 16 weeks) in small groups that focused on improving children’s phonological awareness skills and letter knowledge. Each week, the children
were introduced to a new letter in the alphabet, learned to name and write the letter, and used the letter to participate in rhyming activities (e.g., distinguishing rhyming words
from nonrhyming words, recognizing rhyme, generating rhyme).
The WWC designated the language comprehension group as the comparison condition for this review. The children in the language comprehension condition participated in a
total of 48 lessons lasting 20–25 minutes each (three lessons a week for 16 weeks) in small groups. Each week, the children watched a video of a book followed by pretend
reading of the book with teacher support (e.g., the teacher responded to children’s story-related language and pointing). During subsequent weekly sessions, the children
engaged in activities to learn key vocabulary from the text, fingerpoint reading of the text to promote print awareness, and activities such as acting out the events from the
story and putting in order pictures representing events in the story.
The primary outcome domains assessed were oral language, print knowledge, phonological processing, and early reading/writing. Oral language was measured by two nonstandardized
tests—vocabulary and story event sequencing—and a standardized test of English oral language proficiency—the Pre-Idea Proficiency Test. The WWC does not include the Pre-Idea Proficiency Test in this review because it was not intended to assess the effects of the intervention. Print knowledge was assessed by one nonstandardized measure—letter names. Phonological processing was measured by a nonstandardized test of rhyming. Early reading/writing was assessed by one nonstandardized measure of writing. The study also used a nonstandardized test of print concepts; however, it measured elements of both oral language and print knowledge and cannot be appropriately placed in either domain. So, the WWC does not include this measure in the review. (See Appendices A2.1–A2.4 for more detailed descriptions of outcome measures.)
Support for implementation
The intervention and comparison conditions were conducted by two undergraduate students who alternated between the letter/rhyme and comprehension conditions every two
weeks for 16 weeks. They received about four hours of training and ongoing feedback from the researcher. Initial training included reviewing and discussing the lesson scripts
and goals, observing two lessons, and practicing two lessons.