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ISS Sample

The Intensive substudy (ISS) subsample was composed of students in the RCT full sample whose parents consented at the beginning of pre-k for their children to complete annual individual assessments. The ISS subsample consisted of 1,076 students from 76 R-Lists from 58 VPK programs in 21 school districts across the state of TN. Students in the treatment group (N = 697) offered admission to TN-VPK, and students in the control group (N = 379) applied to TN-VPK but were wait-listed. Some students who were offered admission to VPK either declined or did not show up, and some students who were wait-listed gained admission at different VPK programs. In total, 780 students in the ISS subsample attended at least one day of VPK, and 296 students did not attend VPK. Click here to see the ISS subsample ITT and TOT conditions. 

We used direct assessments, parent questionnaires, and teacher ratings to assess children’s school readiness skills. In this part of the study, children were assessed multiple times, twice during their pre-k year, and then each spring through the 3rd grade.

The outcome measures used to assess academic achievement in the ISS children were selected from the Woodcock-Johnson III (WJ-III) battery of achievement tests. The WJ-III is a nationally normed, individually administered assessment. Two subtests were selected to measure early literacy skills (Letter-Word Identification and Spelling), two were selected to measure early language skills (Picture Vocabulary and Oral Comprehension), and two were selected to measure early math skills (Applied Problems and Quantitative Concepts). These tests are widely used in research to assess the cognitive and academic skills of young children and as outcome measures for early childhood programs.

For the main comparison between children enrolled in TN-VPK and comparable children whose parents applied but were not able to enroll because of limited space in the program, these tests were administered at the beginning of the Pre-K school year (pretest) and again at the end (posttest). They were also administered at the end of kindergarten, first grade, and second grade.

Letter-Word Identification

Letter-Word Identification assesses children’s letter and sight word identification ability. Items include identifying and pronouncing letters and words presented to the child.


Spelling assesses children’s prewriting skills, such as drawing lines and tracing, writing letters, and spelling orally presented words.

Picture Vocabulary

Picture Vocabulary assesses children’s ability to name objects presented in pictures; it measures early language development and lexical knowledge.

Oral Comprehension

Oral Comprehension assesses children’s ability to comprehend a short passage and supply the missing word using syntactic and semantic clues; it measures their listening ability and understanding.

Applied Problems

Applied Problems assesses children’s ability to analyze and solve numerical and spatial problems presented verbally with accompanying pictures of objects.

Quantitative Concepts

Quantitative Concepts assesses children’s knowledge of mathematical concepts, symbols, and vocabulary, including numbers, shapes, and sequences; it measures aspects of quantitative math knowledge and recognition of patterns in a series of numbers.

Two additional WJ-III tests were added for each of the follow-up assessment periods (end of kindergarten, first grade, second grade, and third grade). Brief descriptions of each of these tests are provided below.


Calculation assesses children’s mathematical computation abilities through the completion of visually presented numeric math problems.

Passage Comprehension

Passage Comprehension assesses children’s reading comprehension skills through their ability to match conceptually similar pictures and representations and complete sentences and paragraphs with appropriate words that maintain the semantic properties of the stimulus and make sense in the context of the passage.

For more information on these tests and the WJ-III achievement battery see: Woodcock, R. W., McGrew, K. S., & Mather, N. (2001). Woodcock- Johnson III Tests of Achievement. Rolling Meadows, IL: Riverside Publishing

A parent questionnaire was administered by telephone during students’ pre-k year. Parents of students in Cohort 1 were interviewed during Fall 2009 and the parents of students in Cohort 2 were interviewed in Fall 2010.

ISS Parent Questionnaire Fall 2009

ISS Parent Questionnaire Fall 2010

The measures used to assess teacher perceptions of children’s academic, social, and behavioral qualities in the evaluation of TN-VPK were selected from measures developed and used in prior projects by Peabody Research Institute staff. Two measures were selected to assess children’s school-related academic and behavioral abilities. These measures have been widely used in research studies at the Peabody Research Institute.

The selected measures were collected from children’s kindergarten teachers early in the fall of the school year after Pre-K. These rating scales were also administered at the end of first, second and third grades. These two instruments provided six outcome scores that were examined for evidence of Pre‐K effects. Brief descriptions of each of these scales and subscales are provided below.

Cooper-Farran Behavioral Rating Scale (CFBRS)

The CFBRS was used to investigate children’s behavior in the classroom setting. The behaviorally-anchored scales include teacher ratings of children’s work- related skills and social behavior within the classroom.

Academic and Classroom Behavior Record (ACBR)

The ACBR was used to assess children’s academic and behavioral preparedness for later schooling. The measure includes scores for children’s kindergarten readiness, liking for school, and behavior problems within the classroom