Study of California's Transitional Kindergarten Program
Created in 2010 by the Kindergarten Readiness Act, transitional kindergarten (TK) offers younger children in California additional time to prepare for school. Transitional kindergarten, the first year of a two-year kindergarten experience for students with birthdays between September and December, provides an additional year of early education to thousands of children each year, with the goal of promoting their school readiness.
Supported by its partners, the Heising-Simons Foundation, the David and Lucile Packard Foundation, and First 5 California, AIR completed a study of the impact of transitional kindergarten in California on children’s academic and social-emotional skills in kindergarten, and how these impacts are related to program quality characteristics.
Key findings from the final report show that students who attend California’s transitional kindergarten program enter kindergarten with stronger mathematics and literacy skills and are more engaged in their learning than students who did not attend transitional kindergarten. The program shows an advantage for all students, with particular benefits for English learners and low-income students, and its benefits hold up regardless of variations in instructional practices or classroom structure.
Learn more about our Transitional Kindergarten work:
Final Report: The Impact of Transitional Kindergarten on California Students (June 2017, PDF)
View the research brief/summary of findings (PDF).
This final report from the program’s evaluation focuses on results from a five-year study. The study used a rigorous regression discontinuity design to examine whether TK leads to positive outcomes, for which students, and under what conditions. The findings are based on direct assessments of over 6,000 kindergarteners in California in the fall and spring of the 2014-15 and 2015-16 school years, surveys of their teachers, and statewide data on students’ English language proficiency.
Key findings:

Video: A transitional kindergarten teacher describes his work with his young students, and Karen Manship describes how the program helps ensure children receive a strong start to their educational careers.
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- TK gives students an advantage at kindergarten entry on a range of literacy and mathematics skills. TK students were also rated as more engaged by their teachers, compared to their peers.
- TK is effective for all groups of students who participated. It showed a particularly notable impact on language skills for English learners and mathematics skills for low-income students at kindergarten entry.
- TK has no detectable impact on students’ executive function or incidence of problem behaviors at kindergarten entry.
- Impacts of TK are smaller at the end of kindergarten, though TK students continue to have an advantage over non-TK students on letter and word identification skills. Overall, non-TK students appeared to catch up with their TK peers on most measures, although both TK and comparison students demonstrated growth at or above what would be expected for their age on several assessments. The impact of TK on the literacy and mathematics skills of low-income and Hispanic students also persisted through kindergarten.
- There was little variation in the impact of TK by classroom or instructional characteristics. Standalone classrooms were not significantly different from TK/kindergarten combination classrooms in their impact; half-day and full-day classrooms showed similar effects; and differences in assessed quality of teacher-child interactions did not change the program’s impact. These findings suggest TK’s positive impact for students may be driven by the characteristics that TK programs have in common: credentialed teachers with bachelor’s degrees, close alignment with kindergarten, and inclusion of students from all income-levels.
The Impact of Transitional Kindergarten on English Learner Students (May 2017, PDF)
This brief summarizes what we have learned about the impact of TK on English Learner (EL) students’ school readiness skills, including mathematics skills, language and literacy skills, and English proficiency. Results demonstrated that TK has an impact on EL students’ mathematics skills, language and literacy skills, and English proficiency. EL students who attend TK enjoy a particularly strong advantage over their non-TK EL peers on English proficiency. Because of this, TK may play an important role in improving academic outcomes for English learners, as students who start school with stronger academic skills tend to do better over time.
What Do Transitional Kindergarten Classrooms Look Like in the Third Year of the Program’s Implementation? (June 2016, PDF)
This short report focuses on what we learned about the structure, teachers, and instruction in TK classrooms in the 2014–15 school year. Three years into its implementation, teacher surveys and classroom observations indicated:
- The majority of TK classrooms provided a structure that may be conducive to supporting student readiness for kindergarten.
- The average TK classroom was smaller than kindergarten classrooms, but the ratio of teachers to students was lower than is required for State Preschool.
- Standalone TK classrooms provide a more balanced curriculum and a more developmentally appropriate experience for TK students than TK/K combination classrooms.
- Teachers in both standalone TK and TK/K combination classrooms demonstrated moderately high quality interactions in terms of emotional support and classroom organization.
- Districts could provide TK teachers more guidance on how to promote children’s thinking and problem solving, use feedback to deepen understanding, and help children develop more complex language skills.
Impact of California's Transitional Kindergarten Program, 2013-14 (December 2015, PDF)
Key findings from 2013-14 indicated that TK improves preliteracy and literacy skills, and mathematical knowledge and problem-solving skills. Results show TK also supports children’s behavioral self-regulation, but there is no detectable impact on social-emotional skills. An accompanying brief, The Impact of Transitional Kindergarten on Kindergarten Readiness (PDF), outlines the results of this report and suggests next steps for further research.
Transitional Kindergarten in California: Early Outreach, Enrollment, and Parent Perspectives (March 2015, PDF)
This brief investigating TK implementation in Year 1 focuses on district outreach efforts, parent perceptions of TK, and TK student demographics. Findings from this study point to the challenges districts faced in recruiting children for TK during the first year of implementation.
- Most districts reported that parents frequently wanted to enroll their children in kindergarten rather than in TK.
- District administrators also described other parents who were not aware of the TK program or who were concerned that TK was a remedial program and did not want to send their children to a program they did not understand. Despite these challenges, there were no particular demographic groups of students disproportionately left out of TK.
- District survey results compared with statewide kindergarten enrollment data from the California Department of Education reveal no significant differences in ethnicity, poverty, or English learner status between students in TK and students in kindergarten.
Transitional Kindergarten in California: Comparing Transitional Kindergarten and Kindergarten Classrooms (October 2014, PDF)
Early on, the rollout of the Act gave rise to questions about how TK is being implemented in districts throughout California. This research brief focuses on characteristics of transitional kindergarten classrooms compared with those of kindergarten classrooms. Based on surveys of TK and kindergarten teachers included in this study, it appeared that TK teachers were adopting instructional practices more developmentally appropriate for the younger students enrolled in the program; however, findings also pointed to the challenge of providing differentiated instruction, especially in combination classrooms.
Study of California’s Transitional Kindergarten Program: Report on the First Year of Implementation (April 2014, PDF)
A study looking at the first year of transitional kindergarten in California found that most districts implemented the new grade level, and that approaches varied widely. Overall, transitional kindergarten appeared to provide a different experience than traditional kindergarten. View an executive summary of the findings (PDF) >>
Transitional Kindergarten in California: A Review of the First Year (June 2013, PDF)
This research brief focuses on describing the landscape of California’s TK program in its first year of implementation.