The study was conducted with children from 29 full-day preschool classrooms (14 Doors to
Discovery™ and 15 comparison) selected from Head Start and public preschool programs in
the greater Houston, Texas area.
This randomized controlled study, conducted during the 2003–04 and 2004–05 school years,
included three groups: Doors to Discovery™, Let’s Begin with the Letter People®, and a
comparison group. Study authors recruited 32 Title I and non-Title I (universal) preschools
and Head Start centers that included a total of 79 classrooms. Within each of the three school
types (Title I, non-Title I, and Head Start), schools were randomly assigned to either the Doors
to Discovery™ intervention group, the Let’s Begin with the Letter People® intervention group,
or a comparison group, with all classrooms within a preschool being assigned to the same
intervention condition. Fourteen schools (27 classrooms) in the study were assigned to implement
the Doors to Discovery™ curriculum, 12 schools (25 classrooms) implemented Let’s Begin with the Letter People®, and six schools (27 classrooms) were assigned to the comparison condition.
Subsequent to randomization, teachers were provided with a description of the national
PCER study; of those teachers that opted to participate in the national PCER study during
the 2003–04 school year, 45 were randomly selected (15 from each group). All 79 classrooms
participated in the local investigator’s pilot study during the first year. Following the pilot year,
and prior to starting the national PCER study, one teacher (and her classroom) dropped out of
the study, leaving 14 Doors to Discovery™ classrooms,15 Let’s Begin with the Letter People® classrooms, and 15 comparison classrooms.
The evaluation of Doors to Discovery™ included 29 of the 44 classrooms (14 Doors to Discovery™
classrooms and 15 comparison classrooms, while the remaining 15 classrooms were assigned
to Let’s Begin with the Letter People®). Seven children (whose parents had provided consent to
participate in the study) were randomly selected from each classroom at baseline for inclusion in
the study. The number of children participating in the study at baseline was 196 (100 Doors to
Discovery™ and 96 comparison). The parental consent rate was 65% for the intervention group
and 55% for the comparison group. At baseline, children in the study averaged 4.6 years of age;
55% were male; 43% were Hispanic, 30% were Caucasian, and 13% were African American. The
analysis sample for the Doors to Discovery™ study included 183 children (94 Doors to Discovery™
and 89 comparison).For the PCER Consortium (2008, Chapter 6) study, the Doors to Discovery™ intervention had been in place for a full (pilot) year when the evaluation year started. Although the PCER Consortium (2008, Chapter 6) study used a randomized controlled trial design to assign schools
to intervention or comparison conditions in the pilot year—with all classrooms in a school
assigned to the same condition—the study analyzed data from the second year of implementation,
when children who had been in the classrooms at random assignment had moved to kindergarten and a new class of children had replaced them. Thus, the study had high attrition at the child level and must demonstrate baseline equivalence between the intervention and comparison group sample of children used in the analyses of outcomes. An author query was conducted to obtain the study data necessary to establish equivalence at baseline for one outcome measure in each domain (i.e., unadjusted means and standard deviations of the outcome measures for the intervention and comparison groups). The pretest data provided for each domain were used to establish baseline equivalence for the domain. Baseline equivalence was established from the data provided by the study authors. Baseline equivalence of the analytic sample of children in the two groups at the end of kindergarten was not available, so findings from the kindergarten follow-up are not reported.
Intervention group teachers implemented Doors to Discovery™. For this study, each classroom’s
fidelity to the curriculum was rated on a 4-point scale, ranging from “not at all” (0) to “high” (3).
The average score for the Doors to Discovery™ classrooms was 2.13 on this measure.
A second intervention group was assigned to the Let’s Begin with the Letter People® curriculum;
the effects of this intervention on the study sample are not discussed in this report.
Comparison teachers used teacher-developed nonspecific curricula. Their classrooms were
rated with the same fidelity measure used in the Doors to Discovery™ classrooms, which
ranged from 0 to 3. The average score for the comparison classrooms was 1.0.
The outcome domains assessed were children’s oral language, print knowledge, phonological
processing, and math. Only outcomes in the phonological processing and math domains met
evidence standards with reservations. Phonological processing was assessed with the Pre-
CTOPPP Elision subtest. Math was assessed with the WJ-III Applied Problems subtest, the
CMA-A, and the Building Blocks Shape Composition task. For a more detailed description of
these outcome measures, see Appendix B. Oral language was assessed with the PPVT-III and
the Test of Language Development–Primary III (TOLD-P:3) Grammatic Understanding subtest.
Print knowledge was assessed with the Test of Early Reading Ability-III (TERA-3), the WJ-III
Letter-Word Identification subtest, and the WJ-III Spelling subtest. Baseline equivalence was
not established for outcomes in the oral language and print knowledge domains, and therefore,
these findings are not reported.
Support for implementation
Teachers received curriculum training prior to the start of the 2003–04 school year. This was
the second year of implementation of the intervention, and most of the teachers had been
trained prior to the start of the 2002–03 school year. New teachers each received 12 hours of
training, and returning teachers each received 6 hours of training. The research team collected
site-specific curriculum fidelity data three times during the preschool year. All classrooms were
observed using the Teacher Behavior Rating Scale in fall and spring of the preschool year.