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Promising Program Seal

Head Start REDI

Blueprints Program Rating: Promising

An enrichment intervention integrated into the existing framework of Head Start programs using the High/Scope or Creative Curriculum.

  • Antisocial-aggressive Behavior
  • Emotional Regulation
  • Positive Social/Prosocial Behavior
  • Preschool Communication/Language Development
  • School Readiness

    Program Type

    • Early Childhood Education
    • School - Individual Strategies
    • Skills Training
    • Social Emotional Learning
    • Teacher Training

    Program Setting

    • School

    Continuum of Intervention

    • Universal Prevention (Entire Population)

    An enrichment intervention integrated into the existing framework of Head Start programs using the High/Scope or Creative Curriculum.

      Population Demographics

      This program targets 3-4-year-olds in Head Start programs for at-risk children.

      Age

      • Early Childhood (3-4) - Preschool

      Gender

      • Male and Female

      Race/Ethnicity

      • All Race/Ethnicity

      Race/Ethnicity/Gender Details

      Nix et al. (2013) reported that the intervention effects on posttest outcomes generally did not differ significantly across European-American, African-American, or Latino-American children, although there were a few differences in indirect effects.

      The program focuses on improving socio-emotional and literacy skills.

      • Family
      • School
      • Peer
      • Individual
      Risk Factors
      • Individual: Antisocial/aggressive behavior*
      • Family: Low socioeconomic status
      Protective Factors
      • Individual: Clear standards for behavior, Problem solving skills*, Prosocial behavior, Skills for social interaction*
      • Family: Opportunities for prosocial involvement with parents, Parent social support, Parental involvement in education, Rewards for prosocial involvement with parents
      • School: Opportunities for prosocial involvement in education, Rewards for prosocial involvement in school

      *Risk/Protective Factor was significantly impacted by the program.

      See also: Head Start REDI Logic Model (PDF)

      The Head Start REDI program is designed as an enrichment intervention that can be integrated into the existing framework of Head Start programs that are already using the High/Scope or Creative Curriculum. The intervention is delivered by classroom teachers and integrated into their ongoing classroom programs. It includes curriculum-based lessons, center-based extension activities, and training and weekly classroom coaching in "teaching strategies" to use throughout the day. It is focused primarily on social-emotional skill enrichment using the PATHS Preschool curriculum and language/emergent literacy skill enrichment. Parents also receive take-home materials describing the importance of positive support, emotion coaching, and interactive reading, with parenting tips and learning activities to use at home. In addition, REDI-P (Bierman et al., 2015) adds parent training intended to extend benefits to children for a longer period through parental support.

      The Head Start REDI (Research-Based, Developmentally Informed) program is delivered by classroom teachers and integrated into their ongoing Head Start classroom programs that use the High/Scope or Creative Curriculum. It includes curriculum-based lessons, center-based extension activities, and training in "teaching strategies" to use throughout the day.

      Social-emotional skill enrichment. The program promotes children's social-emotional skills using the 33-session PATHS Preschool curriculum. The curriculum targets four domains: (a) prosocial friendship skills, (b) emotional understanding and emotional expression skills, (c) self-control (e.g., the capacity to inhibit impulsive behavior and organize goal-directed activity), and (d) problem-solving skills, including interpersonal negotiation and conflict resolution skills. The curriculum is divided into 33 lessons that are delivered by teachers once per week during circle time. These lessons include modeling stories and discussions and use of puppet characters, photographs, and teacher role-play demonstration. Each lesson includes extension activities (e.g., cooperative projects and games) that provide children with opportunities to practice the target skills with teacher support. Teachers teach one lesson and conduct one extension activity each week. Generalized teaching strategies are encouraged with mentoring, including positive classroom management, use of specific teacher praise and support, emotion coaching, and induction strategies to promote appropriate self-control.

      Language/emergent literacy skill enrichment. Four language and emergent literacy skills are targeted in REDI: (a) vocabulary, (b) syntax, (c) phonological awareness, and (d) print awareness. Three program components were developed to target these skills, including an interactive reading program, a set of "Sound Games," and print center activities. The curriculum includes two books per week, which are scripted with interactive questions. Each book has a list of targeted vocabulary words, presented with the aid of physical props and illustrations. In addition to presenting these materials in a systematic way during the week, teachers receive mentoring in the use of "language coaching" strategies, such as expansions and grammatical recasts, to provide a general scaffold for language development in the classroom. The overall goal is to improve teacher's strategic use of language in ways that would increase child oral language skills, including vocabulary, narrative, and syntax.

      Teachers are provided with curricula materials to promote phonological awareness and print knowledge. A set of Sound Games is based primarily on the work of Lundberg and colleagues. The games are organized developmentally, moving from easier to more difficult skills during the course of the year (e.g., listening, rhyming, alliteration, words and sentences, syllables, phonemes). Teachers are asked to use a 10- to 15-minute Sound Game activity at least three times per week.

      In addition, teachers are provided with a developmentally sequenced set of activities and materials to be used in their alphabet centers, including letter stickers, a letter bucket, materials to create a Letter Wall, and craft materials for various letter-learning activities. Each child is encouraged to visit the alphabet center several times per week and teachers are given materials to track the children's acquisition of letter names.

      Training and professional development support.  Teachers receive detailed manuals and kits containing all materials needed to implement the intervention. A 3-day professional training is conducted in August, prior to initiating the intervention, and a one-day booster training session is conducted in January. Teachers also receive weekly mentoring support provided by local education consultants ("REDI trainers"), experienced master teachers who are supervised by two project-based senior educational trainers. The weekly consultations are intended to enhance the quality of implementation through modeling, coaching, and providing ongoing feedback regarding program delivery. REDI trainers spend an average of three hours per week in each classroom observing, demonstrating, or team teaching lessons. They also meet with the head and assistant teacher for one hour each week outside of class.

      Parent take-home materials. Three "take-home" packets are mailed to parents during the course of the year, each containing a modeling videotape, with parenting tips and learning activities to use at home. In addition, the PATHS curriculum includes handouts for parents, with suggestions for home activities. Children also take home letter stickers and compliment pages to prompt their parents to ask them about their school day and to provide positive support at home.

      REDI-P (Bierman et al., 2015) adds additional home visits for Head Start parents, enriching these visits with evidence-based learning activities and support strategies. In addition to receiving take-home materials, parents receive 10 home visits during the spring of the Head Start pre-kindergarten year and 6 booster sessions after the start of kindergarten. Parents receive additional encouragement in these home visits to utilize materials and learn strategies that extend the benefits of the Head Start REDI program in the home.

      A central objective of REDI is to maximize the integration of the social-emotional and language/emergent literacy intervention components that comprise the enrichment program. Each week, one of the books used in the interactive reading program focuses on the PATHS theme for that week (e.g., friendship, feelings, self-control, social problem solving), and feeling words are included in the vocabulary prompts. Conversely, PATHS extension activities incorporate language and emergent literacy skills.

      The goal of REDI is to maximize the impact of Head Start on child school readiness outcomes by considering a comprehensive approach that addresses both the cognitive and social-emotional skill development of children affected by poverty and disadvantage. By integrating support for improved instruction and teaching across these domains, children benefit in a broader array of outcome areas.

      • Biological - Neurobiological
      • Person - Environment
      • Skill Oriented

      The Head Start REDI study (Bierman, Domitrovich et al., 2008; Bierman, Nix et al. 2008; Bierman et al. 2014; Nix et al., 2013; Nix et al., 2016) was designed as a randomized trial that involved 25 centers with 44 classrooms. Centers were randomly assigned to either the treatment condition (REDI) or to the usual practice of Head Start. The classrooms were drawn from three counties in Pennsylvania and involved a mix of large and small towns. In total, 356 4-year-olds participated. They were assessed pre-intervention, post-intervention, 1 year after the intervention, and annually up to 4 years after the intervention. Children were observed during playtime and assessed by their parents and teachers.

      An additional study (Bierman et al., 2015) was conducted to evaluate the added benefit of home visits with REDI-P. This randomized trial involved 200 families randomly assigned to either the treatment of additional home visits or the control of the standard Head Start REDI program. The study recruited families from 24 Head Start centers in three urban and rural Pennsylvania counties during the 2008-2009 and 2009-2010 academic years. The study conducted assessments in the fall of prekindergarten and the end of kindergarten. Children completed standardized tests, teachers reported on student achievement and attitudes, parents and children were observed by researchers, and parents reported their own behavior and attitudes.

      Bierman, Domitrovich et al. (2008), Bierman, Nix et al. (2008), Bierman et al. (2014), Nix et al. (2013; 2016): A study that integrated REDI and language emergent literacy skills into a Head Start program already using the High/Scope or Creative curriculum demonstrated the following outcomes. At posttest, statistically significant differences in aggression were reported by teachers, and marginal differences reported by parents, with those in the intervention group showing less aggression. No differences on aggression were reported by observers. Additionally, intervention students were better on various skills targeted by the intervention, including language and emerging literacy skills and social-emotional skills and task orientation (i.e., learning engagement in school) rated by observers.

      At the 1-year follow-up, the intervention showed significant main effects on five outcomes: phonemic decoding, teacher-rated learning behaviors, competent problem solving, teacher-rated aggression, and parent-rated aggression. At the 4-year follow-up, intervention subjects showed more positive trajectories for several measures of socio-emotional functioning such as social competence, aggressive-oppositional behavior, and peer rejection.

      Bierman et al. (2015): At posttest, children in the home visit treatment group had significantly improved language and literacy test scores, teachers reported significant improvement in measures of social-emotional learning, and parents improved on several measures of support for learning, as compared to the control group.

      Bierman, Domitrovich et al. (2008), Bierman, Nix et al. (2008), Bierman et al. (2014), Nix et al. (2013; 2016) 

      • Parents and teachers reported less aggression among those in the intervention group when compared to the control group at posttest and follow-up.
      • Students in the intervention group showed more improvements in emergent literacy skills than control students at posttest and, for a measure of phonemic decoding, at follow-up.
      • Children in the intervention group showed more improvements on child vocabulary and on parent reports of communication and language use at home at posttest.
      • At the 4-year follow-up, intervention subjects showed more positive trajectories for several measures of socio-emotional functioning such as social competence, aggressive-oppositional behavior, and peer rejection.

      Effects on Risk and Protective Factors

      • Students in the intervention group showed more improvement than those in the control group on emotional understanding at posttest and social problem-solving skills at posttest and follow-up.
      • At the 4-year follow-up, intervention subjects showed more positive trajectories for several measures of socio-emotional functioning such as learning behavior, attention problems, and student-teacher closeness.

      Bierman et al. (2015) REDI-P home visit program

      At posttest, there was a significant intervention effect for standardized tests of language and literacy skills in:

      • Emergent literacy
      • Academic performance

      In addition, there was a significant intervention effect for teacher reports of social-emotional adjustment in:

      • Self-directed learning
      • Social competence

      Risk and Protective Factors

      At posttest, there was a significant intervention effect for parent reports of parent support for learning in:

      • Reading quality
      • Conversations

      One mediation analysis (Nix et al., 2013) treated changes in five outcome measures from baseline to posttest as mediators: 1) vocabulary, 2) emergent literacy skills, 3) emotional understanding, 4) competent social problem solving, and 5) positive social behavior. The intervention significantly improved all five of these mediating outcomes, with effect sizes ranging from .25 to .49.

      The analysis examined three kindergarten outcomes: 1) reading achievement, 2) learning engagement, and 3) positive social behavior. The five mediators and three outcomes defined 15 possible indirect effects.

      The results demonstrated that gains made during preschool predicted kindergarten functioning. For reading achievement, the intervention had significant indirect effects via four of the five mediators. For learning engagement, the intervention had significant indirect effects via three of five posttest measures. For positive social behavior, the intervention had significant indirect effects via one of five posttest measures (positive social behavior). Gains made during Head Start thus continued to predict functioning one year later, in kindergarten.

      At posttest (Bierman, Domitrovich et al., 2008), effect sizes ranged from .15 to .39 for child skill outcomes. At follow-up (Bierman et al., 2014), effect sizes ranged from .22 (small) to .40 (small medium). In most cases, these effect sizes were equivalent to or larger than those at posttest. In comparing trajectories through the 4-year follow-up, Nix et al. (2016) reported odds ratios in the small-medium range (1.6 to 1.9).

      Bierman et al. (2015) reported small to small-medium standardized, mean centered coefficients (comparable to Cohen’s of .25-.29).

      Bierman,Domitrovich et al. (2008), Bierman, Nix et al. (2008), Bierman et al. (2014), Nix et al. (2013, 2016)

      • The analysis appears to have dropped some families who withdrew from the program.
      • Models measured intervention at the classroom level when it appears that centers, typically with multiple classrooms, were randomized; however, subsequent analysis requested by Blueprints showed minimal impact from adding center as a clustering factor.
      • Tests for baseline differences did not include sociodemographic characteristics.
      • Six of 13 outcome measures were missing pretest scores.
      • Measures of executive functions, although important for development of skills and behaviors, had limited relationships with the intervention in analyses of outcomes, moderation, or mediation.

      Bierman et al. (2015)

      • Some measures came from reports of parents, who helped to deliver the intervention
      • One outcome measure not equivalent at baseline

      • Blueprints: Promising

      Bierman, K., Domitrovich, C., Nix, R., Gest, S., Welsh, J., Greenberg, M., ... Gill, S. (2008). Promoting academic and social-emotional school readiness: The Head Start REDI program. Child Development, 79(6), 1802-1817.

      Bierman, K. L., Nix, R. L., Greenberg, M. T., Blair, C., & Domitrovich, C. E. (2008). Executive functions and school readiness intervention: Impact, moderation, and mediation in the Head Start REDI program. Development and Psychology 20(3), 821-843.

      Bierman, K. L., Nix, R. L., Heinrichs, B. S., Domitrovich, C. E., Gest, S. D., Welsh, J. A., & Gill, S. (2014). Effects of Head Start REDI on children’s outcomes 1 year later in different kindergarten contexts. Child Development, 85(1), 140-159.

      Bierman, K. L., Welsh, J. A., Heinrichs, B. S., Nix, R. L., & Mathis, E. T. (2015). Helping Head Start parents promote their children’s kindergarten adjustment: The research-based developmentally informed parent program. Child Development, 86, 1877-1891.

      Nix, R. L., Bierman, K. L., Domitrovich, C. E., & Gill, S. (2013). Promoting children’s social-emotional skills in preschool can enhance academic and behavioral functioning in kindergarten: Findings from Head Start REDI. Early Education and Development, 24(7), 1000-1019.

      Nix, R. L., Bierman, K. L., Heinrichs, B. S., Gest, S. D., Welsh, J. A., & Domitrovich, C. E. (2016). The randomized-controlled trial of Head Start REDI: Sustained effects on developmental trajectories of social-emotional functioning. Forthcoming Journal of Consulting and Clinical Psychology, 84(4), 310-322.

      Karen Bierman, Ph.D.
      Penn State University
      Department of Psychology
      251 Moore Building
      University Park, PA 16801
      kb2@psu.edu
      sites.psu.edu/redi/

      Study 1

      Bierman, K., Domitrovich, C., Nix, R., Gest, S., Welsh, J., Greenberg, M., ... Gill, S. (2008). Promoting academic and social-emotional school readiness: The Head Start REDI program. Child Development, 79(6), 1802-1817.

      Bierman, K. L., Nix, R. L., Greenberg, M. T., Blair, C., & Domitrovich, C. E. (2008). Executive functions and school readiness intervention: Impact, moderation, and mediation in the Head Start REDI program. Development and Psychology 20(3), 821-843.

      Bierman, K. L., Nix, R. L., Heinrichs, B. S., Domitrovich, C. E., Gest, S. D., Welsh, J. A., & Gill, S. (2014). Effects of Head Start REDI on children’s outcomes 1 year later in different kindergarten contexts. Child Development, 85(1), 140-159.

      Nix, R. L., Bierman, K. L., Domitrovich, C. E., & Gill, S. (2013). Promoting children’s social-emotional skills in preschool can enhance academic and behavioral functioning in kindergarten: Findings from Head Start REDI. Early Education and Development24(7), 1000-1019.

      Nix, R. L., Bierman, K. L., Heinrichs, B. S., Gest, S. D., Welsh, J. A., & Domitrovich, C. E. (2016). The randomized-controlled trial of Head Start REDI: Sustained effects on developmental trajectories of social-emotional functioning. Forthcoming Journal of Consulting and Clinical Psychology, 84(4), 310-322.

      Head Start REDI Study: Bierman, Domitrovich et al. (2008), Bierman, Nix et al. (2008), Bierman et al. (2014), Nix et al. (2013), Nix et al. (2016)

      Intervention: Teachers delivered the 33 lesson Preschool PATHS curriculum once per week to promote children's social-emotional skills. REDI targeted vocabulary, syntax, phonological awareness, and print awareness with three program components. Teachers received weekly mentoring support provided by local education consultants (REDI trainers), experienced master teachers who were supervised by two project-based senior educational trainers. The program was integrated into Head Start centers that were implementing the High/Scope or Creative Curriculum.

      Evaluation Methodology

      Design: The study consisted of a randomized sample taken of 44 Head Start classrooms in 25 (Nix et al., 2013, 2016) centers across three counties in Pennsylvania. Half of the participating classrooms came from a large, fairly densely populated county in the southeastern part of the state, which included an urban community surrounded by smaller communities. The other classrooms came from two smaller counties in the central part of the state, characterized by small towns and rural areas. Classrooms were stratified on location, length of program, and student demographics to assure even representation in the intervention and comparison conditions. In the more urban county, classrooms were stratified into three groups, in terms of urban (vs. nonurban) location, percentage of minority students served, and use of Spanish in the classroom. In the two more rural counties, classes were also stratified into three groups, which varied in terms of being full-day or half-day programs and located in small towns versus rural locations.

      Classrooms in the same center were always assigned to the same condition, to avoid inadvertent contamination of condition within centers. Within stratified groups, centers were randomly assigned to intervention or comparison conditions. This process resulted in 14 classrooms (67%) in each condition that were located in small centers (1-2 classrooms) and 8 classrooms in each condition located in four larger centers (containing 3-5 classrooms), with children from ethnic minority groups fairly evenly spread across condition (39% of the intervention group and 45% of the control group.) A total of 356 children took part in the study.

      Children were recruited across two years. Each year, teachers were studied as they implemented the intervention for the first time, and 4-year-old children were assessed after receiving one year of REDI intervention and then one year later at the end of kindergarten. Teachers in the comparison classrooms continued to conduct the curriculum "as usual." These control classrooms contained about 14 children, typically one-third three-year olds and two-thirds four-year olds. To recruit participants for the evaluation trial, brochures describing the study were distributed to parents of all 4-year-old children in participating classrooms. Overall, only 14 eligible families declined to participate in the evaluation process, but an additional 21 primary caregivers were very difficult to reach and failed to complete the preassessment. Two children were dropped because they had a twin or sibling in the study, and 19 families withdrew early from Head Start and completed only parts of the assessment procedures. Hence, study participants represented 86% of the initially eligible population.

      Assessments occurred early in the school year (pretest) and at the end of the school year (posttest). At the 1-year follow-up, the subjects transitioned to 202 kindergarten classes at 82 schools in 33 school districts. The follow-up assessment occurred in March-April, near the end of kindergarten. The 4-year follow-up assessed the children each year through the end of third grade.

      Among the 356 children, attrition was only 3% at posttest and only 5% at follow-up. At the 4-year follow-up, attrition reached only 9%.

      Sample: Participants in this study included two cohorts of 4-year old children. They were 17% Latino, 25% Black, and 58% white. Also, 54% were girls and 46% were boys. Primary caregivers included 89% mothers, 4% fathers, 4% grandparents, and 3% other, such as stepparents or foster parents. In terms of education of the primary caregivers, 31% had less than a high school education, 60% graduated from high school, 8% completed a technical degree, and 2% completed a college degree. The authors note that the sample is typical of the socioeconomically disadvantaged families and children for whom Head Start is intended.

      Measures: A multi-method, multi-measure assessment battery included child assessments, teacher ratings, parent ratings, and direct observations. Outcome measures at posttest represented six core domains: (a) language skills, (b) emergent literacy skills, (c) emotional understanding and social-cognitive skills, (d) social-emotional behaviors, (e) learning engagement at school, and (f) learning engagement at home. Bierman et al. (2008a) said posttest observational measures were obtained from observers naive to condition, and Bierman et al. (2014, p. 156) said with reference to the 1-year follow-up measures that child interviewers and kindergarten teachers did not know intervention group status. However, Head Start teachers both implemented the program and provided some measures at posttest.

      Language skills. Three tests were administered directly to children to assess their language skills. In the Expressive One-Word Picture Vocabulary Test, children gave the word that best described pictures they were shown. The Grammatical Understanding subtest of the Test of Language Development assessed syntax comprehension. Children listened to a sentence and chose one of the four pictures that "best matched" the meaning of the sentence. The Sentence Imitation subtest assessed syntax expression. Children repeated sentences read aloud by the interviewer. Scores reflected the number of increasingly complex sentences a child imitated correctly.

      Emergent literacy skills. Three subscales assessing emergent literacy skills were drawn from the Test of Preschool Early Literacy (TOPEL). The Blending subtest assessed phonological processing. Children were asked to combine different parts of a word, such as "hot" and "dog" or "b" and "air" and point to the correct picture or say the full word. On the Elision subtest of TOPEL, children deconstructed compound words and pointed to the correct picture. On the Print Knowledge subtest of the TOPEL, children identified pictures of letters or words and named letters.

      The 1-year follow-up (Bierman et al., 2014) used somewhat different measures at the end of kindergarten. Instead of the Blending measure, the follow-up used a measure of Phonemic Decoding Efficiency based on the number of words sounded out accurately. Instead of the Elision measure, the follow-up used a measure of Sight Word Efficiency based on the number of words read accurately. Instead of the Print Knowledge measure, the follow-up used a measure of letter-word identification from the Woodcock-Johnson Test of Achievement.

      Emotional understanding and social-cognitive skills. Two measures assessed emotional understanding. On the Assessment of Children's Emotion Skills, children determined whether the facial expressions in 12 photographs reflected happy, mad, sad, scared, or no feelings. The score was the total number correctly identified. On the Emotion Recognition Questionnaire children listened to 16 stories describing characters in emotionally evocative situations and identified their feeling by pointing to pictures of happy, mad, sad, or scared faces. Children received a score of 2 for correctly identifying the feeling and a score of 1 for correctly identifying the valence. In addition, social-problem solving skills were assessed using a variation of the Challenging Situations Task. Children were presented with pictures of four peer scenarios (e.g., a peer knocking down blocks, being hit, entering a group, a peer taking a ball). After each scenario, children were asked what they would do in the situation. Their open-ended responses were coded as competent (i.e., appropriately asserting oneself or calmly negotiating a solution), aggressive (i.e., responding with verbal or physical antagonism, intimidation, or force), or inept.

      Social-emotional behaviors. Teacher ratings, observer ratings, and parent ratings assessed social competence and aggressive-oppositional behavior. The 13 items of the Social Competence Scale were rated on a 6-point Likert scale (never to almost always) and included prosocial behaviors such as sharing, helping, and understanding other's feelings, as well as self-regulatory behaviors, such as resolving peer problems independently. Ratings provided by lead and assistant teachers were averaged.

      Seven items from the Teacher Observation of Child Adaptation-Revised (TOCA-R) assessed overt aggression (e.g., stubborn, yells, fights). Six items from the Preschool Social Behavior Scale-Teacher Form assessed relational aggression (e.g., "Tells other kids he/she won't be their friend unless they do what he/she wants"). Items were rated on a 6-point Likert scale (almost never to almost always). Ratings from lead and assistant teachers were averaged and overt and relational ratings were combined to form a total aggression score. Parents and observers completed the seven items from TOCA-R only.

      Learning engagement at school. Teacher ratings were used to assess learning engagement at school, using an eight-item inventory developed for this study. Items were rated on a 6-point Likert scale (strongly disagree to strongly agree), and reflected self-regulation (e.g., "Has the self-control to do well in school" and "Can follow the rules and routines that are part of the school day"), learning motivation and involvement (e.g., "Seems enthusiastic about learning new things"), and compliance (e.g., "Is able and willing to follow teacher directions"). Lead and assistant teacher ratings were averaged.

      Observers completed the Adapted Leiter-R Assessor Report to assess task orientation at school. After the child assessments, interviewers rated the child's participation and involvement, using 13 items (e.g., "Shows pleasure in accomplishment and active mastery," "Careful and interested in accuracy," "Alert and interactive"). Each item was rated on a 4-point scale. Scores from the two assessment sessions were averaged.

      Teachers also completed the ADHD Rating Scale. Based on the Diagnostic and Statistical Manual symptoms of attention deficit hyperactivity disorder, this scale includes 14 items reflecting attention problems (e.g., "Is easily distracted," "Has trouble following directions"), each rated on a 4-point scale. Lead and assistant teacher ratings were averaged and used in this study to represent a continuous dimension reflecting difficulties with impulse control, distractibility, and sustained attention.

      Learning engagement at home. Parents completed the ADHD Rating Scale. In addition, they responded to five questions about children's language and communication at home (e.g., "How many times in a typical week do you and your child have a conversation that lasts 10 minutes or more?", "How often does your child volunteer to tell you about something that happened when you were not with him or her?"). Finally, parents answered six questions about children's engagement in reading at home (e.g., "When was the last time you and your child read a book together?", "How many books did you read at that time?").

      Mediation. Bierman et al. (2008b) examined three of the 12 skill measures and four of the 11 behavior measures. Unique to their study, they examined five measures of executive function as outcomes, moderators, and mediators: 1) Backward Word Span measured the ability to repeat a list of words in backward order; 2) Peg Tapping measured the ability of children to tap their peg twice when the interviewer tapped once and vice versa (alpha for 16 trials = .87); 3) Dimensional Change Card Sort (DCCS) measured the ability of children to correctly sort cards by, for example, color after initially sorting them by, for example, size (alpha for six trials = .93); 4) Walk-a-Line Slowly measured the ability of children to walk on a straight line at a slow pace; and 5) Task Orientation measured the ability to focus on a task during a testing session (ratings of multiple dimensions had an alpha of .93).

      Follow-up. Outcome measures at 1-year follow-up (Bierman et al., 2014) included 13 items in four domains: a) language and emergent literacy skills, b) learning engagement, c) social competence, and d) aggressive behavior. The follow-up used 10 of the 23 measures used at pretest and posttest. As described above, three other measures of emergent literacy skills were new to the follow-up but were related to the pretest and posttest measures.

      Although not treated as outcomes, three measures of kindergarten context served as potential moderators in the follow-up. Observers rated kindergarten classrooms of the study subjects on the quality of student-teacher interactions and the quantity of reading instruction. In addition, standardized tests measured the percent of third-grade scores below the basic category in reading and math proficiency.

      In the mediation analysis (Nix et al., 2013), posttest outcome measures served as mediators, and differed in some ways from posttest measures used in other articles. These mediating measures included 1) vocabulary, 2) emergent literacy skills based on a combination of the blending and Elision measures, 3) emotional understanding based on a combination of measures of emotional skills and emotional recognition, 4) competent problem solving, and 5) positive social behavior based on a combination of observer, teacher, and parent ratings of social competence and aggressive behavior (reverse coded).

      The mediation analysis used several final outcome measures obtained at the kindergarten follow-up. They included 1) reading achievement based on three measures, 2) learning engagement based on a combination of measures of intellectual curiosity, self-discipline, and attention, and 3) positive social behavior based on the same items as at posttest.

      Analyses: To examine preintervention differences between the intervention and the comparison groups, hierarchical linear models (HLM) were estimated, accounting for the nesting of children within classrooms. Child sex and race were included as Level 1 covariates and center site, cohort, and intervention status were included as Level 2 covariates in each of these models.

      The first set of analyses to examine postintervention group differences used HLM to examine the 11 measures of child language, emergent literacy, emotional understanding, and social problem-solving skills that were targeted directly by the intervention and were measured using direct assessments of child skill knowledge. Because the intervention was delivered at the classroom level, analyses accounted for the nonindependence of data at that level. Child sex and race were included as Level 1 covariates and site, cohort, and intervention status were included as Level 2 covariates. Preintervention scores were available for all these measures and also were included as Level 1 covariates. For ease of interpretation, all measures were standardized with a mean of 0 and a standard deviation of 1. By doing this, the coefficient for the intervention effect represents the difference in average expected scores between children in the intervention and control groups as a proportion of a standard deviation.

      HLM analyses were also conducted to assess intervention effects on the 12 behavioral ratings provided by teachers, observers, and parents. As before, the HLM nested children within classrooms, included child sex and race as Level 1 covariates and included site, cohort, and intervention status as Level 2 covariates. In this case the researchers only had preintervention parent ratings and preintervention observing ratings of task orientation as Level 1 covariates.

      The follow-up analysis used cross-classified hierarchical models in which Level-2 random effects accounted for clustering within both preschool classrooms and kindergarten school districts. The Level-1 equation controlled for baseline outcomes (or something similar when measures changed at follow-up). With outcome measures standardized, the coefficients are comparable to Cohen’s d.

      The mediation analysis used full information maximum likelihood estimation to minimize any bias that comes from missing data. It also used multilevel models that nested children within their Head Start classrooms. The models controlled for baseline values of the mediating variables by treating them as residualized gain scores, but it appears that the models did not use baseline controls for the kindergarten outcomes.

      With data on five time points (posttest, kindergarten, first grade, second grade, and third grade), the 4-year follow-up (Nix et al., 2016) compared developmental trajectories across conditions. For each of six outcomes, latent class growth models identified from two to four trajectory patterns and each child was assigned to the trajectory that he or she most likely followed. The test of the intervention effect was based on the significance of differences in the proportion of children in each developmental trajectory who had been in Head Start REDI versus Head Start as usual. Odds ratios for intervention children following a particular developmental trajectory relative to control children showed the magnitude of the program effect. The analysis was done at the individual level without adjustment for clustering within classrooms (though the ICC = .003) or schools.

      Outcomes

      Implementation Fidelity: Teachers reported completing most lessons, and trainers rated the average fidelity and quality of implementation as between adequate and strong.

      Baseline Equivalence: No significant pretreatment intervention-control group differences emerged on the 11 measures of child skills or the 6 measures of child behavior for which pretreatment scores were available. The study did not report on equivalence of sociodemographic characteristics.

      At follow-up (Bierman et al., 2014), intervention and control subjects in kindergarten were compared on measures of teacher-student interaction quality, curriculum emphasis on reading instruction, and school-level achievement. The conditions did not differ significantly on these three measures, thus confirming that on entering kindergarten, intervention students were not selected into better schools.

      Attrition: Attrition was low – only 3-5%. But Nix et al. (2013, p. 1003) stated that there were “few significant differences” between those retained and not retained. Nix et al. (2016) presented no information on differential attrition for the 9% lost by the 4-year follow-up.

      Posttest: In Bierman, Domitrovich et al. (2008), there were significant treatment effects for 7 of 11 skills directly targeted by the intervention and marginally significant intervention effects for two others. Three of 12 behavioral ratings provided by teachers, observers, and parents significantly favored intervention students and five measures showed marginally significant trends favoring the intervention students. Statistically significant differences in aggression were reported by teachers, with those in the intervention group showing less aggression. There were marginally significant differences reported by parents, and no significant differences reported by observers. Students who participated in the intervention showed statistically significant improvements on direct assessments of the children's emotional understanding and social problem-solving skills and emergent literacy skills compared to the control group. When looking at language skills, those in the intervention group had more improvement on measures of child vocabulary and on parent reports of communication and language use at home. Observers also reported more improvements in task orientation among those in the intervention group compared to those in the control group.

      Omnibus tests or overall tests of the significance grouping the individual measures in the conceptual domains were requested by Blueprints and subsequently delivered by the evaluators, finding significance in all but one (language skills) of the six domains (emergent literacy skills, social cognitions, social-emotional behaviors, learning engagement at school, and learning engagement at home).

      Long-term: Bierman et al. (2014) examined the effects of the intervention on the 1-year follow-up measures (i.e., at the end of kindergarten). The intervention showed significant main effects on 5 of 13 outcome measures: phonemic decoding, teacher-rated learning behaviors, competent problem solving, teacher-rated aggression, and parent-rated aggression. Effect sizes ranged from .22 to .40. In most cases, these effect sizes were equivalent to or larger than those at posttest, and in most cases, they reflected benefits in the social-emotional domain.

      Omnibus tests or overall tests of the significance grouping the individual measures in the conceptual domains were requested by Blueprints and subsequently delivered by the evaluators, finding significance in all but one (language/emergent literacy) of four domains (social competence, aggression, and learning engagement).

      Significant moderation (p < .05) by kindergarten context emerged for 5 of 39 tests. The authors noted that, even in the absence of main effects, the interaction effects indicated program benefits for subsets of subjects. Specifically, the results indicated that the intervention had stronger effects and greater benefits when there were many low-achieving children in the school on four outcomes: teacher-rated attention problems, parent-rated attention problems, teacher-rated social competence, and teacher-rated aggression in schools. While these four interaction effects showed greater benefits in less positive kindergarten contexts, one other showed greater benefits in a positive kindergarten context. The results revealed stronger intervention effects on competent problem solving in classes with high-quality teacher-student interaction.

      To isolate the changes unique to kindergarten, a final analysis added controls for posttest scores. Only one of the main effects of the intervention remained significant, and two were marginally significant. The weaker results suggest that most benefits came during preschool but that these gains were maintained in kindergarten. The moderating effects of kindergarten context, in contrast, were largely maintained with the controls for posttest scores.

      Executive Function: In Bierman, Nix et al. (2008), the analysis examined the influence of measures of executive function on the skill and behavioral outcomes and the influence of the executive function measures as moderators of the intervention, as outcomes of the intervention, and as mediators of the intervention.

      To determine if the program benefit varied by level of executive function, the models added product terms of treatment by each of the five executive function measures. Two of 35 interaction tests (five moderators by seven outcomes) reached statistical significance and three more reached marginal significance (p < .10). For these five interactions, children with low baseline levels of executive functioning benefitted more from the intervention; children with high baseline levels did well regardless of the intervention.

      The intervention significantly improved (p < .05) posttest scores on one of the five executive function measures - Task Orientation - and came close (p = .06) on one more – DCCS. Effect sizes equaled .28 and .20, respectively, for the two outcomes.

      Mediation tests examined the two executive function measures that were significantly or near significantly influenced by the program (Task Orientation and DCCS). Of the 14 tested mediation effects (two mediators by seven outcomes), three proved significant. Task Orientation significantly mediated the program effect on print awareness, with the relationship between the program and print awareness declining by 33% with controls for the two mediating variables. Task Orientation significantly mediated the program effect on observer-rated social competence and observer-rated aggression. The reductions due to the mediators equaled 29% for observer-rated social competence and 43% for observer-rated aggression.

      In summary, 1 of 5 tests showed that executive function was significantly affected by the intervention, 2 of 35 tests showed that executive function moderated the intervention impact, and 3 of 14 tests showed that executive function mediated the intervention impact. Overall, 11% of the 54 tests involving the measures of executive function reached significance.

      Developmental Trajectories: Tests of the latent class growth models showed program benefits for each of six outcomes tested over the five time points between posttest and 4-year follow-up: social competence, aggressive-oppositional behavior, learning behavior, attention problems, student-teacher closeness, and peer rejection. Compared to control children, intervention children had higher odds of belonging to positive trajectories and lower odds of belonging to negative trajectories.

      Mediating Effects : The mediation analysis (Nix et al., 2013) treated changes in five outcome measures from baseline to posttest as mediators: 1) vocabulary, 2) emergent literacy skills, 3) emotional understanding, 4) competent social problem solving, and 5) positive social behavior. The intervention significantly improved all five of these mediating outcomes, with effect sizes ranging from .25 to .49.

      The analysis examined three kindergarten outcomes: 1) reading achievement, 2) learning engagement, and 3) positive social behavior. The five mediators and three outcomes defined 15 possible indirect effects.

      The results demonstrated that gains made during preschool predicted kindergarten functioning. For reading achievement, the intervention had significant indirect effects via four of the five mediators. For learning engagement, the intervention had significant indirect effects via three of five posttest measures. For positive social behavior, the intervention had significant indirect effects via one of five posttest measures (positive social behavior). Gains made during Head Start thus continued to predict functioning one year later, in kindergarten.

      However, the study also found that the two conditions did not differ significantly on reading achievement and learning engagement in kindergarten. These results differ from Bierman et al. (2014), perhaps because Nix et al. (2013) used broader versions of the outcome measures.

      Limitations

      • The analysis appears to have dropped some families who withdrew from the program.
      • Models measured intervention at the classroom level when it appears that centers, typically with multiple classrooms, were randomized, however, subsequent analysis requested by Blueprints showed minimal impact from adding center as a clustering factor.
      • Tests for baseline differences did not include sociodemographic characteristics.
      • Six of 13 outcome measures were missing pretest scores.
      • Measures of executive functions, although important for development of skills and behaviors, had limited relationships with the intervention in analyses of outcomes, moderation, or mediation.

      Bierman et al. (2015) added additional home visits to the standard Head Start REDI intervention.

      Bierman, K. L., Welsh, J. A., Heinrichs, B. S., Nix, R. L., & Mathis, E. T. (2015). Helping Head Start parents promote their children’s kindergarten adjustment: The research-based developmentally informed parent program. Child Development, 86, 1877-1891.

      Evaluation Methodology

      Design:

      Recruitment: The study recruited families from 24 Head Start centers in three urban and rural Pennsylvania counties during the 2008-2009 and 2009-2010 academic years. Each year, the study sent letters describing the study to all prekindergarten children in participating classrooms. Letters were sent to approximately 400 eligible households, of which 52% elected to participate.

      Assignment: The study randomly assigned 95 households to the treatment condition and 105 households to the control condition. Treatment families received the Head Start REDI materials in addition to home visits, while control conditions received only the Head Start REDI materials.

      Attrition: The pretest assessment occurred in the fall of the preschool year and the posttest occurred in the spring of the kindergarten school year. The study reported that 4% of households left the study.

      Sample: The sample was comprised of 55% white, 26% black, and 19% Hispanic children. The sample was 56% male and averaged 4.45 years of age. The median annual family income among the population was $18,000, 39% single parent, and 54% unemployed.

      Measures: All but 2 of 11 measures came from independent observers – teachers and researchers who were unaware of condition. Two measures came from reports of parents, who helped deliver the program. Reliability was acceptable for most measures but was low (alpha = .56) for one of the parent-reported measures.

      The study used four measures of child language and emergent literacy skills. First, the study used the Expressive One-Word Picture Vocabulary Test, which assessed vocabulary. Second, the study used the Letter-Word Identification scale of the Woodcock-Johnson Tests of Achievement III-revised, which tests emergent literacy skills. Third, the study used the Test of Word Reading Efficiency, which tests reading fluency. Finally, teachers, who were blind to condition, rated children’s academic performance with the 12-item performance rating scale.

      The study also used three teacher-rated measures to assess social-emotional adjustment. First, teachers used the School Readiness Questionnaire, which measured child self-directed learning. Second, teachers rated children on 13 items describing prosocial behavior. Finally, teachers rated children on the Teacher Observation of Child Adaptation-Revised, which describes aggressive behavior.

      Finally, parent support for learning was assessed by four measures using parent reports, videotaped observations of parent-child interactions, and observations conducted in the home. Parents first described the degree to which they read interactively with their children, using five items from the Participation subscale of the Reading Belief Inventory and second described the quality of conversation with their children. Third, trained coders rated videotapes of parent-child interactions during structured tasks. Finally, observers rated parents with a modified version of the Post-Visit Inventory to measure parental warmth and support.

      Analysis: The study used cross-classified hierarchical linear models, nesting children within their Head Start classrooms and elementary school districts. The models included pretest outcomes as covariates but the vocabulary measure served as the control for the other language and literacy measures that were obtained only in kindergarten. Other controls included kindergarten school quality, county, cohort, age, sex, race, aggression, single-parent status, caregiver depressive symptoms, and family income-to-needs ratio.

      Intent-to-Treat: The study included all available data, excepting only the reported 4% attrition.

      Outcomes

      Implementation Fidelity: The study reported that families completed an average of 12 of 16 total visits, and visitors reported a parent-engagement score of 2.27 out of a possible 3.

      Baseline Equivalence: The study reported that one outcome measure (parent support for learning) favored the comparison group at pretest, but all other sociodemographic and outcome measures were equivalent across the intervention and control groups at pretest.

      Differential Attrition: With less than 4% attrition, the study did not provide additional analysis of attritors.

      Posttest: A significant intervention effect was found for 2 of 4 measures of language and literacy skills. Children in the treatment group had significantly better scores in emergent literacy and academic performance at posttest as compared to children in the control group. In addition, the study found a significant intervention effect for 2 of 3 measures of social-emotional learning. Children in the treatment group had better scores at posttest in teacher-rated self-directed learning and social competence.

      Finally, the study found a significant intervention effect for 2 of 4 risk and protective factors in parent support for learning. Parents in the treatment group reported higher scores for reading quality and conversations. Observer-rated scores on parent support did not differ across conditions.

      Long-Term: The study did not report a long-term follow-up.

      Limitations:

      • Some measures came from reports of parents, who helped to deliver the intervention
      • One outcome measure not equivalent at baseline