Volume 42, 1st Quarter 2018, Pages 256–269

Effective language and literacy instruction: Evaluating the importance of scripting and group size components

  • a TrygFondens Center for Child Research and School of Communication and Culture, Aarhus University, Denmark
  • b Department of Speech and Hearing Sciences, University of New Mexico, Albuquerque, USA
  • c Crane Center for Early Childhood Research and Policy, The Ohio State University, USA
  • d Department of Educational Studies
  • e Rambøll Management Consulting, Aarhus, Denmark
  • f Department of Teaching & Learning, The Ohio State University, USA
  • g Department of Language and Communication, University of Southern Denmark, Odense, Denmark
  • h Clinical Epidemiology, Center of Medical Biometry and Medical Informatics, University Medical Center, Freiburg, Germany


Language/literacy preschool intervention taken at scale had positive effect.

Effect reduced compared to typical effects in efficacy trials.

Larger effect when activities were not aligned the sequence and scope but decided by educators.

Effect not influenced by child group size or children being/not being at risk.

Significant association between exposure and effect.


Identification of intervention program components most strongly associated with children’s outcomes is essential for designing programs that can be taken to scale. In this effectiveness study, a population-representative sample of 5436 3–6-year-old Danish children from 154 daycare centers participated in a cluster-randomized evaluation of three variations of a language-literacy focused curriculum (LEAP) comprising 40 twice-weekly 30-min lessons. LEAP-LARGE and LEAP-SMALL conditions involved educators’ implementation of a scope and sequence of objectives using scripted lessons provided to whole-class and small groups, respectively. In LEAP-OPEN, educators followed the scope and sequence but were allowed to determine the instructional activities for each of 40 lessons (i.e., they received no scripted lessons). A business-as-usual (BAU) condition served as the control. Overall, the largest effect sizes for children’s language and emergent literacy outcomes were found for LEAP-OPEN, although the other two LEAP conditions had positive effects for literacy outcomes. Analysis of moderation effects showed no moderation effects for children’s socioeconomic status or for non-Danish children. Finally, there was a significant association between children’s amount of exposure to the program and both language and literacy outcomes, with higher exposure associated with better outcomes: specifically, non-Danish children benefitted more than native Danish children from higher exposure for language outcomes. This study indicated that an essential component in language and emerging literacy intervention at scale is an explicit sequence and scope of learning objectives, whereas group-size and provision of scripted lessons may be less important.


  • Language and literacy intervention;
  • Randomized controlled trial;
  • Effectiveness study;
  • Intervention components;
  • Group size;
  • Scale-up

1. Introduction

The language and literacy skills of preschool-aged children are strongly predictive of their future skills as readers and writers (see National Early Literacy Panel [NELP], 2008). Consequently, researchers have devoted considerable attention to designing and testing systematic, explicit interventions for preschoolers to improve their language and literacy skills in such areas as phonological awareness, print knowledge, and vocabulary knowledge (e.g., Justice, McGinty, Piasta, Kaderavek, & Fan, 2010; Lonigan, Purpura, Wilson, Walker, & Clancy-Menchetti, 2013; Lundberg, Frost, & Petersen, 1988). Systematic, explicit language and literacy interventions typically provide a scope and sequence of objectives and scripted lessons with aligned activities for educators to follow to directly teach these objectives, often as a whole-class activity (e.g., Bierman et al., 2008; DeBaryshe and Gorecki, 2007; Gonzalez et al., 2011 ;  Justice et al., 2010). Despite the encouraging body of evidence for the effects of systematic, explicit language and literacy intervention on young children’s development of these skills, our understanding of whether and to what extent these interventions work when taken to scale is limited. For instance, it is unclear whether practitioners can adopt the critical components of language and literacy intervention with fidelity, such as adhering to scripted lessons and implementing instruction in a large-group setting. There is a complementary need to identify the individual components of systematic, explicit language and literacy curricula that are most strongly associated with improved child outcomes (Center on the Developing Child, 2016; Phillips et al., 2017).

The focus of the present study was to determine the effects associated with two components commonly seen in systematic explicit language and literacy interventions (i.e., group size and scripted lessons with aligned activities) on child outcomes when implemented at scale in a Danish preschool setting. The main aim was to identify those components that appear most effective for improving children’s outcome. Additionally, we wanted to explore if individual child-level differences (i.e., background characteristics and individual intervention exposure) moderated the effects of the components on children’s outcomes.

1.1. Evaluating the components of interventions

Many preschool-focused language and literacy interventions are multi-component, including specification of a scope and sequence delineating a set of specific targeted skills organized over the period of instruction, and instructional practices (i.e., techniques and aligned activities). In many interventions, the scope and sequence and the aligned instructional practices are manualized via scripted lessons that educators implement with the children. These scripts serve to identify the specific instructional techniques and activities within each lesson, with the techniques and activities serving to deliver the scope and sequence of objectives to children (e.g., Assel, Landry, Swank, & Gunnewig, 2007; Bierman et al., 2008; Hamre et al., 2010 ;  Justice et al., 2010). Despite the prominence of scripted lessons in language and literacy interventions in early education settings, the potentially causal role they play as an intervention component has not, to our knowledge, been investigated.