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Research
Three studies reviewed by the WWC investigated the effects of Curiosity Corner. One study is a randomized controlled trial that meets WWC evidence standards. A second study is a quasi-experimental study that meets WWC evidence standards with reservations. The remaining study does not meet WWC eligibility screens.
Meets evidence standards
One study reviewed by the WWC, PCER Consortium (2008), assesses Curiosity Corner’s effectiveness as part of the Preschool Curriculum Evaluation Research (PCER) effort.7 PCER Consortium (2008) used a randomized controlled trial design in which 18 preschools in Florida, Kansas, and New Jersey were randomly assigned to implement Curiosity Corner or to a control group. The study sample included children in 31 classrooms. Following parent consent, data were collected on 211 children. Half of the children were male, half were African-American, and 14% were reported to have a disability. Pretests were collected in the fall and posttests in the spring of the preschool year. The study investigated effects on oral language, print knowledge, phonological processing, and math. The comparison condition varied across sites and included both teacher-developed and branded curricula.
Meets evidence standards with reservations
Chambers, Chamberlain, Hurley, and Slavin (2001), the second study, investigates the effects of Curiosity Corner using a quasi-experimental design that meets WWC evidence standards with reservations. The study included 316 children in 16 private and public preschools (three-year-old children at private child care centers and four-year-old children at public schools from four urban, high-poverty school districts in New Jersey). More than two-thirds of the children were African-American. Pretests were collected in the fall and posttests in the spring. The authors compared oral language and cognitive outcomes for children in a Curiosity Corner intervention group with those for children in a comparison group that used the classroom’s standard early childhood curriculum.
Extent of evidence
The WWC categorizes the extent of evidence in each domain as small or medium to large (see the What Works Clearinghouse Extent of Evidence Categorization Scheme). The extent of evidence takes into account the number of studies and the total sample size across the studies that met WWC evidence standards with or without reservations.8
The WWC considers the extent of evidence for Curiosity Corner to be medium to large for oral language and small for print knowledge, phonological processing, cognition, and math. No studies that met WWC evidence standards with or without reservations addressed early reading and writing.
7 Preschool Curriculum Evaluation Research (PCER 2008) evaluated a total of 14 curricula, including Curiosity Corner, in comparison to the respective local control conditions.
8 The Extent of Evidence Categorization was developed to tell readers how much evidence was used to determine the intervention rating, focusing on the number and size of studies. Additional factors associated with a related concept–external validity, such as the students’ demographics and the types of settings in which studies took place–are not taken into account for the categorization. Information about how the extent of evidence rating was determined for Curiosity Corner is in Appendix A6.