Evaluation of programs for improving language and early literacy skills in young children

Transcription

1 Forsknings-review - Sprogpakken.dk Evaluation of programs for improving language and early literacy skills in young children Literature review for Sprogpakken Aims & Purposes The purpose of this review is to examine the research on programs and practices that aim to improve oral language and early literacy skills in young children. This review will provide evidence concerning the efficacy of a range of programs and practices available to day-care teachers. This review also aims to raise awareness among day-care teachers about the range of different programs and practice that have been developed. This review examined the following questions: 1. Does a curriculum/systematic approach to supporting language and early literacy skills in young children produce better outcomes than a non-curriculum/non-systematic approach? Our interest in addressing this question was to examine whether available evidence indicates whether a systematic curriculum based approach to early learning is equivalent, superior or inferior to individual lesson plans developed by individual day care teachers. 2. Do all curriculum/systematic approaches have equivalent outcomes or do some have a better effect on language and early literacy skills? A large number of different curriculum programs have been developed (for an overview see Table 2). We were interested in examining whether all have an equal effect on early language or literacy outcomes. 3. What specific practices can teachers working in early day care centres use to promote language and early literacy skills? In addition to examining entire curricula, which incorporate a range of different practices, the current review also examined specific practices which teachers may be able to use. In this review we examined which specific practices produced the best outcomes on children s language and literacy skills. 1

2 Forsknings-review - Sprogpakken.dk Identifying Studies to Include in the Review Approach & Methodology In undertaking this review, it was necessary that a representative sample of intervention studies that have examined the effectiveness of language and pre-literacy programs be identified. In meeting this goal, a key issue addressed was how to best find previous research. A key concern when undertaking any review is to reduce the impact of selection bias. In the context of a systematic or traditional review, selection bias occurs when researchers either knowingly or unknowingly include articles that support a particular point of view (Egger, Smith, Schneider, & Minder, 1997). In the case of evaluating interventions and trials, this might be only including studies that report a therapeutic effect of an intervention. Perhaps the main challenge in undertaking reviews, particularly of interventions, is that selection bias can unintentionally occur. For example, research has shown that there is a publication bias towards reporting results that only show positive effects (Egger & Smith, 1998). This might mean that it can be easier to find studies showing positive effects compared to null effects leading to selection bias in the review. In an attempt to overcome the aforementioned problems, methodologists and researchers developed a more objective approach for integrating research, which is called a systematic review (Higgins & Green, 2008). In a systematic review, the researcher/s are required to explicitly describe all the steps used to find studies, and also which criteria was used to include or exclude studies from their review. The steps used to describe the literature review process involves explicitly stating which databases were searched, the key words used in the databases, the years that have been searched and also how many articles were found and which ones were included. In addition, researchers may often contact different organisations to find non-published studies as well. In the pedagogical field, a number of systematic reviews have already been been undertaken that have evaluated best practices in promoting language and early literacy skills in young children. These systematic reviews were the starting point in which to identify potentially useful studies for the current review. A summary of each of these reviews is presented in Table 1. Additional research articles for the current review were found following a literature search undertaken at the Centre for Child Language at The University of Southern Denmark in Odense, Denmark in November In this search the PsycInfo and PubMed databases were used to indentify studies published between 2007 and A list of the key words and search strategy in this search is presented in Appendix A. This search returned a total of 359 articles. Criteria for Selecting Studies to be Included in the Review. The systematic reviews reported in Table 1 along with the literature search undertaken at the Centre for Child Language were used to identify past research to be included in this review. Once these studies were found, inclusion criteria were applied. Applying the criteria was necessary to assist in synthesising and generalising the results. These criteria are now described in turn. Criterion 1: Intervention studies required both treatment and control groups. To be included in the review all studies examining the efficacy of different intervention/practices were required to have at least one Intervention and one Control group in a between-subjects design study. 2

3 Table 1. Systematic Reviews used to Identify Studies Authors Years Searched Number of studies reviewed Burger (2010) a 32 Bus et al. (1995) Not stated in paper. However, studies selected in the review were published between Chambers et al. (2010) Manz et al. (2010) McGroder & Hyra (2009) Not stated in paper. However, studies selected in the review were published between Mol et al. (2008) National Early Literacy Panel (2008) Reese et al. (2010) No stated in paper. However, studies selected in the review were published between Notes: a Authors note one exception in which a study published in 1987 was included. 3

4 Forsknings-review - Sprogpakken.dk Criterion 2: Participants were required to be randomly allocated to treatment and control groups. The second criterion required that the intervention studies randomly assign children to treatment and control conditions. Randomised controlled trials are considered one of the best methods to evaluate the relationship between an intervention and outcome (e.g., Clarke, 1998; Cochrane, 1973). Criterion 3: Endpoint measures needed to include assessment of language, pre-literacy or literacy skills. The third criterion required that studies evaluate the efficacy of the intervention/practice via assessment of children s language and literacy skills. Specifically, after the intervention had been presented, children in the Intervention and Control Groups needed to be presented with a test assessing their language, pre-literacy or literacy skills. It should be noted that some of the studies identified in the systematic reviews only measured the effectives of intervention on cognitive and behavioural development. Since these domains are beyond the scope of this review, they were excluded. Criterion 4: Psychometric Properties of the Endpoint measures needed to be published or reported in research article: The fourth criterion was that the test assessing language, preliteracy or literacy skills needed to have the psychometric properties of the test published. This criterion effectively meant that only studies were included that had used a published standardised test to evaluate the outcomes of an intervention. The most fundamental reason for including this criterion was so the test s reliability and validity could be known. Criterion 5: Study needed to report results that could be extracted for meta-analysis. The final criterion required that published studies report enough detail in the results to allow data to be extracted and converted to an effect size. In this review all result from the studies were converted to an effect size measure called Cohen s d (Rosenthal, 1994). A description of this index is provided now provided. A brief overview of effect sizes and Cohen s d In this review the effectiveness of interventions and practices are quantified using a numerical index called an effect size. An effect size numerically describes the amount of variance in a dependent/outcome variable that is explained by the independent/predictor variable. In the context of examining interventions, an effect size quantifies the magnitude of difference between treatment and control groups following treatment/intervention. The larger the effect sizes, the larger the difference between treatment and control groups. The effect size can be considered to operate as a function of many observed and unobserved variables. In randomised controlled trials, the effectiveness of the intervention/ treatment is considered to be a key determinant of the magnitude of the effect size. Another contributing factor is the measurement error or reliability of the tests used to measure outcome. As the measurement error of the test increases, the effect size decreases (Hunter & Schmidt, 1990). In the context of this review, measurement error is a concern for at least two reasons. The first is that tests that have a high level of measurement error produce small effect sizes. Thus if an intervention is effective and the test used to measure language or literacy outcomes is poorly constructed, this will produce small effect sizes. Perhaps the most troublesome case arises when comparing the results of two or more studies that examine different language or literacy interventions using different tests that have different levels of measurement error. If one of the tests has a high level of measurement error (i.e., is a bad test) and the other low (i.e., is a good test), even if the effectiveness of the different intervention is the same, studies that have bad tests will produce results suggesting the intervention does not work even though it does. This in turn will lead to incorrect conclusions about the effectiveness of an intervention. The criterion that studies need to have psychometric properties reported was to be able to control for the aforementioned problems. Published standardised tests not only almost always have psychometric properties published, but often these are verified by independent research teams and published in peer review journals. This stands in contrast to studies where researchers have devised their own test and do not report the psychometric properties of their instrument. 4

5 Forsknings-review - Sprogpakken.dk Quantifying the Efficacy of Programs/Practices: Effect sizes, statistical significance, precision, consistency of effects and clinical importance. A central outcome of this review is to be able to compare different programs/practices. In order to achieve this goal, it is necessary to quantify the results of all the different studies so they are on the same scale. The process and rationale by which this is achieved is analogous to converting different measures of distance (e.g., feet, inches) into centimetres. The scale used in this review to evaluate the different intervention studies is called Cohen s d (Cooper, Hedges, & Valentine, 2009). This index describes the difference between two groups in terms of a standardised mean difference. Cohen s d is one type of effect size. As a guide to interpreting this value, when the Cohen s d value is equal to zero, this means there is no difference between two groups. In the context of intervention studies, a value of zero would mean that there is no evidence to suggest that an intervention/practice is associated with better language/literacy outcomes. In this review positive Cohen s d values indicate that the Intervention Group obtained higher scores on a language/literacy test that a Control Group. Negative Cohen s d value indicates that a Control Group obtained higher scores. In the research literature there is a reasonably well-accepted taxonomy interpreting Cohen s d values (Cohen, 1988), whereby a value of 0.2 is considered a small effect size, 0.5 is medium and 0.8 is large. Cohen s d can also be considered to measure the amount of overlap between two distributions. For example, when Cohen s d = 0 there is 100% overlap in scores between the Control Group and Intervention Group (i.e., there is no difference between groups) and when Cohen s d =.8 there is 52.6% overlap in distributions (i.e., there is a difference between the groups). In short, in the context of this review, larger positive effect size values indicate that an intervention/practice is effective. 5 Another issue that needs to be taken into account when comparing different Cohen s d values between different studies is how precise or accurate the value is. Any Cohen s d value observed for a particular study describes how effective an intervention was for the individual s participating in that study. However, in this review the focus is in on being able to generalise the result from a specific study or sample to a broader population. Thus, the question of interest in this review is how well a Cohen s d value accurately represents the type of effect that would be observed if an intervention was administered to all children. One factor that influences how well we can generalise the results from a specific study to a population is the sample size. It is important to remember that when a study is undertaken a sample of children/adults is taken from a population. The larger the sample is, the more accurately the findings of the study will represent the whole population (assuming

6 Forsknings-review - Sprogpakken.dk random selection of participants). Thus, a study which has 1000 participants almost always will be more accurate than a study that has 20 participants. When comparisons are made between studies, it is important that the precision of the Cohen s d value is taken into account. For example, consider the following scenario. Suppose a study reported a Cohen s d value of.8 but only and 10 people participating and another study reported a value of.3 but had 3000 people participating. Which study should we put the most confidence in? All things being equal, the answer would be the second study with 3000 because it has more people and therefore the effect size value is more likely to be accurate. Statisticians have developed various methods for measuring how precise an observed effect size is, given the number of people there are in a study. One approach is to use confidence intervals (Gardner & Altman, 1986). Confidence intervals provide us with an estimate of how precise an effect size, like Cohen s d, might be. When we compute a value for Cohen s d, we can then determine the confidence interval for that value. The confidence intervals tell us with a specified level of probability, what the real (or population) value might be. Confidence intervals comprise two values, a lower and an upper value. For example, suppose a study that reports an effect size of.5. Based on the study s sample size, we can then work out confidence intervals. The lower value might be.3 and the upper value might be.7. The population value is thought to be somewhere between.3 and.7. In research, it is common to compute confidence intervals so they tell us that the real value is likely to lie between the upper and lower value and we can assert this with a probability of 95%. That is, we expect to be correct 95 times out of 100 (or incorrect 5 times in 100). In this review we report confidence intervals for all observed effect sizes. Combining Results in Different Studies Measuring Variability Between Studies In some of the analyses in this review, Cohen s d values from different studies are combined and an overall average is computed. Effect sizes from different studies can be combined using fixed- or random-effects models. In this review all effect sizes were combined using a random-effects model (for details see Hedges & Vevea, 1998). In random-effects models, the averaged Cohen s d value (or any averaged effect size) is considered to represent the central tendency of a population of difference effect sizes. In principle, adopting a random-effects model to derive an average effect size computed from multiple individual studies allows one to make generalisations beyond the methodology of the individual studies. Another aspect of the research finding examined is the amount of variability there is between studies. When comparing Cohen s d values from groups, the effect sizes will vary. Some of this variation is attributable to chance, such as differences due to the random selection of participants to be involved in the study. However, another source of variation might reflect more meaningful differences. In this review the amount of heterogeneity between studies is to be quantified using the I2 statistic. This statistic expresses, as a percentage, the amount of variation or heterogeneity between studies that is not due to chance. A rough taxonomy has been forwarded whereby 25% variation is considered low, 50% moderate and 75% high (Higgins, Thompson, Deeks, & Altman, 2003). 6

7 Forsknings-review - Sprogpakken.dk Studies, Curricula/Programs and Measures included in the Review Studies used in the review After applying the criteria outlined in Figure 1, a total of 41 studies were identified that met the criteria. A brief description of each study is presented in Table articles found from keyword search in PubMed og PsycInfo with limiters at CfB Articles screened manually for relevance 160 articles selected by title, abstract and/or keywords. 3 articles removed here due to selection criteria, but included in the Danish materials. 7 articles found at CfB by searching reference lists. 3 articles included in the final review 4 studies 3 studies Number of articles included in the review studies identified by Burger (2010), Bus et al. (1995), Chambers et al. (2010), Manz et al. (2010), McGroder & Hyra (2009), Mol et al. (2008), National Early Literacy Panel (2008), and Reese et al. (2010) 34 studies 8 articles removed due to selection criteria, although included in the Danish materials. Figure 1 Process for identifying studies The 41 files came from three main sources: reviews, database searches, and the reference lists from the articles we found. The 11 articles that were disallowed here due to selection criteria are included in the Danish material, Forskningskortlægning af behov for sprogvurdering, effektive sprogindsatser og pædagogisk efteruddannelse. 7

8 Table 2. Description of Studies Included in the Review Study Country Mean age of participants (Months) Socio-Economic Status of the Sample Ethnicity Bilingual Intervention/Practices Trialed Abt Associates Inc. (2007) Abt Associates Inc. (2007) Abt Associates Inc. (2007) Not stated. Only noted that participants were of school age Not stated. Only noted that participants were of school age Not stated. Only noted that participants were of school age Mixed Mixed Mixed Mixed Mixed Mixed Breakthrough to Literacy Building Early Language and Literacy Mixed Mixed Mixed Ready Set Leap! Aram (2006) Israel 47 Low SES Mixed Not stated Aram & Birron (2004) Israel 45 Low SES Mixed 83.3% of sample spoke Hebrew as their first language; 16.7% spoke Russian as their first language. 1. Dialogic Reading; 2. Alphabetic Skills Program; 3. Combined Storybook Reading & Alphabetic Skills 1. Dialogic Reading; 2. Alphabetic Skills Program Arnold et al. (1994) 29 Middle to Upper Not stated Not stated 1. Dialogic Reading Intervention Group/s Breakthrough to Literacy (n = 350) Building Early Language and Literacy (n = 319) Ready Set Leap! (n = 350) 1. Storybook Reading Program (n = 37) 2. Alphabetic Skills Program (n = 38) 3. Combined (n = 40) 1. Joint Reading (n = 38); 2 Joint Writing (n = 38) 1. Direct Training (n = 23); 2 Video Training (n = 14). Control Group Provided with materials only. Did not follow curriculum (n = 580 Provided with materials only. Did not follow curriculum (n = 648) Provided with materials only. Did not follow curriculum (n = 648) Untreated/standard educational practice (n = 41) Untreated/standard educational practice (n = 24) Children read to in normal manner (n = 27) 8

9 Study Country Assel et al. (2007) Baker et al. (1998, Cohort 1) Baker et al. (1998, Cohort 2) Bierman (2008) Chow & McBride- Chang (2003) Hong Kong, China Chow et al. (2008) Hong Kong, China Crain-Thoreson & Dale (1999) Mean age of participants (Months) Socio-Economic Status of the Sample Ethnicity Bilingual Intervention/Practices Trialed Intervention Group/s 55 Mixed Mixed Mixed Doors to Discovery Doors to Discovery 58 Low SES Mixed Across both Cohorts 34.6% of the sample did not speak English as their first language. 1. HIPPY Program 1. HIPPY (n = 37) 54 Low SES Mixed 1. HIPPY Program 1. HIPPY (n = 47) 48 Low SES Mixed English & Spanish 1. REDI Program 64 Not stated Chinese Cantonese 1. Dialogic Reading 64 Unclear Chinese Cantonese 52 Children with special educational needs, SES not explicitly 1. Dialogic Reading with Morphology Training (morphological awareness); 2. Dialogic Reading; 3 Typical Reading (n = 37) Not stated Not stated 1. Dialogic Reading 1. REDI Program & Head Start 1. Dialogic Reading (n = 27) 2. Typical Reading (n = 25) 1. Dialogic Reading with Morphological Training (n = 38); 2. Dialogic Reading (n = 37). 1. Parent Dialogic Reading (n = 10); 2. Teacher Dialogic Reading (n = 13). Control Group Control classroom characterised by a lack of specified curriculum that included a scope and sequence of activities. (Assel et al., 2007, p. 475) Standard practice (n = 32) Standard practice (n = 66) Head Start Only (standard practice) No systematic reading or provision of books (n = 28) No books were provided. Parents engage in normal practice with children (n = 36) Standard practice (which did include group story time; n = 9) 9

10 Study Country Cronan et al. (1996) Fischel et al. (2007) Mean age of participants (Months) Socio-Economic Status of the Sample 28 Low SES Aged between 45 and 60 Ethnicity Bilingual Mainly Latino (Note: Study conducted in the U.S.) English & Spanish Mixed Mixed Mixed Intervention/Practices Trialed 1. Dialogic Reading Let s Beging with the Letter People Intervention Group/s 1. High number of instructional visits/ Dialogic Reading (n = 83); 2. Low number of instruction visits/dialogic Reading (n =73). Let s Begin with the Letter People (n = 185) Fischel et al. (2007) Aged between 45 and 60 Mixed Mixed Mixed Waterford Waterford (n = 172) Girolametto et al. (1995) Canada 29 Children with language delays, SES not stated Not stated English 1. Focused Stimulation 1. Focused Stimulation (n = 8) Huebner (2000) 29 Mixed, including infants at risk for language problems. Mainly white English 1. Dialogic Reading 1. Dialogic Reading (n = 88) Lonigan & Whitehurst (1998) Lonigan et al. (1999) 45 Low SES Not stated English 1. Dialogic Reading 45 Low SES Mainly African Americans Not stated 1. Shared/Typical Reading 2.Dialogic Reading 1. School Reading; 2. Home Reading; 3. School & Home Reading 1. Shared/Typical Reading (n = 29); 2. Dialogic Reading (n = 34) 10 Control Group Typical home rearing practices (n = 69) High/Scope curriculum materials (n = 150) High/Scope curriculum materials (n = 150) Delayed treatment (n = 7) 2. Control Group (provided with same resources as treatment group, but not provided with information about dialogic style of reading, i.e., child as centre of the story telling; n = 41). Standard practice Standard preschool curriculum (n = 32)

11 Study Country McGill-Franzen et al. (1999) PCER (2008) PCER (2008) PCER (2008) PCER (2008) PCER (2008) PCER (2008) PCER (2008) 11 Mean age of participants (Months) Not clearly stated (e.g., In the paper it is only noted that...some children were only 4 years of age at pretesting and other children were near age 6., p. 69) Socio-Economic Status of the Sample Mixed: Low SES and Non- Low SES Ethnicity Bilingual Not stated Not stated Intervention/Practices Trialed 1. Generalist Literacy Promotion 55 Mixed Mixed Not stated Language Focused Curriculum 55 Mixed Mixed Not stated DLM with Open Court Reading 55 Mixed Mixed Not stated Literacy Express 54 Mixed Mixed Not stated Ready Set Leap! 54 Mixed Mixed Not stated Bright Beginnings 55 Mixed Mixed Not stated Doors to Discovery 55 Mixed Mixed Not stated Let s Begin with the Letter People Intervention Group/s 1. Teacher Training & Books (n = 164); 2. Books (n = 139). Language Focused Curriculum (n = 97) DLM with Open Court Reading (n = 101) Literacy Express (n = 90) Ready Set Leap! (n = 149) Bright Beginnings (n = 103) Doors to Discovery (n = 101) Let s Begin with the Letter People (n = 100) Control Group No books OR teacher training (n = 153) High/Scope curriculum materials (n = 93) High/Scope curriculum materials (n = 97) High/Scope curriculum materials(n = 86) High/Scope curriculum materials(n = 120) Nonspecific curricula with a focus on basic school readiness (n = 105) Teacher-developed, nonspecific curricula (n = 96) Teacher-developed, nonspecific curricula (n = 73)

12 Study Country Mean age of participants (Months) Socio-Economic Status of the Sample Ethnicity Bilingual Intervention/Practices Trialed Intervention Group/s PCER (2008) 55 Mixed Mixed Not stated Project Approach Project Approach (n = 114) PCER (2008) 55 Mixed Mixed Not stated Creative Curriculum Creative Curriculum (n = 78) PCER (2008) 54 Mixed Mixed Not stated Creative Curriculum Creative Curriculum (n = 97) Reese et al. (2010) Robertson & Wesimer (1999) Valdez-Menchaca & Whitehurst (1992) van Balkom et al. (2010) 50 Low SES Mixed 25 Late talking infants, Middle Class homes Across the different intervention and control groups, percentage of bilingual children ranged from % White English 1. Elaborative Reminiscing 2. Dialogic Reading 1. Interactive Child Centered Intervention 1. Elaborative Reminiscing (n = 12); 2. Dialogic Reading (n = 10) 1. Interactive Child Centered Intervention (n = 11) Mexico 31 Low SES Native Spanish 1. Dialogic Reading Dialogic Reading 25 The Netherlands Developmental Language Delay, Middle Class Families Not stated Not stated 1. Video Home Training 2. Direct Child Language Intervention 1. Video Home Training (n = 11) 2. Direct Child Language Intervention (DCI; n = 11) Wasik & Bond (2001) 51 Low SES African American Not stated 1. Dialogic Reading 1. Dialogic Reading (n = 61) Wasik & Bond (2006) 46 Low SES African American Not stated 1. Dialogic Reading 1. Dialogic Reading (n = 139) 12 Control Group Teacher-developed, nonspecific curricula (n = 90) Nonspecific curricula with a focus on basic school readiness (n = 105) Teacher-developed, nonspecific curricula.(n = 97) No training/standard Parental care (n = 11) Delayed Treatment (n = 10) Arts & Craft Instruction No non-treatment control group Participated in arts, craft and science activities (n = 63). Provided with same books(n = 68)

13 Study Country Whitehurst et al. (1988) Whitehurst et al. (1994) Whitehurst et al. (1999) Zevenbergen et al. (2003) 13 Mean age of participants (Months) Socio-Economic Status of the Sample Ethnicity Bilingual Intervention/Practices Trialed 29 Middle SES Not stated Not stated 1. Dialogic Reading 42 Low SES Mixed Mainly from English speaking homes 1. Dialogic Reading Not stated. Paper onhly reports children were in the 2nd Grade Low SES Not stated 90% of sample spoke English as their first language 56 Low SES Mixed Not stated 1. Combined Dialogic Reading & Sound Foundations 1. Dialogic Reading & Head Start Program (n = 71) Intervention Group/s 1. Dialogic Reading (n = 29) 1: Teachers & Parents (n = 20); 2 Teachers only (n = 26) 1. Combined Dialogic Reading & Sound Foundations 1. Dialogic Reading & Head Start Program (n = 71) Control Group Normal reading No reading (n = 24). Children in the control condition engaged in supervised play sessions. Regular Head Start Curriculum Regular Head Start Curriculum (n = 52)

14 Forsknings-review - Sprogpakken.dk Curricula, Interventions and Practices Evaluated in Studies that Met Criteria. The studies included in the review, collectively evaluated 22 different programs/practices that aim to improve language and literacy skills in young children. These program/ practices are summarised in Table 3. There is considerable diversity in the range of programs/practices covered in the studies that met the criteria for inclusion into this review. Some programs/practices can best considered as a complete structured curriculum for implementation into day care (e.g., Bright Beginnings, see Table 3 for summary). Other program/practices comprise a single task. The dialogic reading program best typifies this approach (e.g., Whitehurst, et al., 1988). Another type of program/practices identified involving combining structured curriculum with a single task. For example, Bierman (2008) examined the effectiveness of combining a dialogic reading program with a phonological awareness program. Differences between the program/practices also exist with respect to implementation. The studies included in this review included program/practices that have been implemented by teachers, (e.g., Baker, et al., 1998) and speech pathologists (Robertson & Weismer, 1999). 14

15 Table 3. Summary of Programs/Practices Evaluated in the Studies Included in the Review. Name Description Intervention/Curriculum/Practice Study/Studies evaluating Intervention/Curriculum/Practice Breakthrough to Literacy Bright Beginnings Building Early Language and Literacy (BELL) Breakthrough to Literacy is a systematic and integrated literacy and language program published by the Wright Group, which aims at promoting language development and literacy skills among preschool children. The program uses systematic, direct instruction built around a series of weekly books in the classroom. Interactive computer programs are also used to engage students in individualized activities, and are organized around the weekly book, to support their literacy skills and print knowledge. (Chambers et al., 2010, p. 13) Bright Beginnings is an integrated curriculum with a focus on language and early literacy. The curriculum goals are to provide a child-centered, literacy-focused program that is consistent and to include instruction that addresses the needs of the whole child. The curriculum was especially designed to provide continuity in the preschool to second-grade curricula. Bright Beginnings includes nine curriculum units that focus on language and literacy, mathematics, social and personal development, healthful living, scientific thinking, social studies, creative arts, physical development, and technology. The classroom environment is designed to encourage children s active exploration and interaction with adults, other children, and concrete materials. The curriculum also includes a parent involvement component that requires parents to be actively engaged in the child s education (Chambers et al., 2010, p 13).a Building Early Language and Literacy (BELL) is a preschool supplementary program aimed at promoting preschoolers general language proficiency, phonological awareness, shared reading skills, and print knowledge. Children receive two minutes lessons daily. Children s literature is used in classrooms to build vocabulary and promote awareness of story sequencing and characters. The program also includes shared reading time and phonological awareness time to support reading skills and phonetic reading techniques. (Chambers et al., 2010, p. 16) Curriculum/Program Abt Associates (2007) Curriculum/Program PCER (2008) Curriculum/Program Abt Associates (2007) 15

16 Name Description Intervention/Curriculum/Practice Creative Curriculum DLM with Open Court Reading Creative Curriculum is a comprehensive approach to education for three- to five-year-old children. The curriculum addresses four areas of development - social/emotional, physical, cognitive, and language development. Creative Curriculum requires the physical space of the classroom to be structured into 10 interest areas: blocks, dramatic play, toys and games, art, library, discovery, sand and water, music and movement, cooking, and computers. Time is also allotted for outdoor activities. The 10 interest areas are designed to address curriculum content, such as literacy, mathematics, science, social studies, the arts, and technology, in a fairly unstructured setting designed to promote children s process skills, such as observing, exploring, and problem solving. Creative Curriculum includes a Developmental Checklist teachers are asked to use in ongoing assessments of child progress (Chambers et al., 2010, p. 16). The DLM Early Childhood Express Program is a comprehensive curriculum, designed to promote children s social, emotional, intellectual, aesthetic, and physical development. Open Court Reading Pre-K contains eight thematic units that address children s identity, families, friends, social interactions, transportation, the physical senses, nature, and transitions. (from Study/Studies evaluating Intervention/Curriculum/Practice Curriculum/Program PCER (2008) Curriculum/Program PCER (2008) 16

17 Name Description Intervention/Curriculum/Practice Doors to Discovery Language Focussed Curriculum The Doors to Discovery curriculum is a preschool program that is based on the areas identified as important for literacy success: oral language, phonological awareness, concepts of print, alphabet knowledge, writing, and comprehension. The program focuses on the use of learning centers and shared literacy activities in the preschool classroom. The curriculum is presented in eight thematic units that cover topics such as friendship, communities, nature, society, and health. Classroom practices include large and small group teacher-directed activities and children s application of skills and independent practice on activities that are related to the themes. The curriculum components also include family learning activities that are designed to foster partnerships between the school and the family; initial training for teachers and ongoing professional development support; and assessment strategies that are integrated into the curriculum units. (Chambers et al., 2010, p. 21) The Language-Focused Curriculum (LFC) was developed at the University of Kansas for use with three- to five-year-old children with language limitations, including children with language impairment, children from disadvantaged backgrounds, and English language learners. The curriculum has a thematic organization and focuses on the use of daily dramatic play to teach and use linguistic concepts. There are both teacher-led and child-led activities with explicit attention to oral language development that is enhanced by high-quality teacher-child conversations. Teachers use eight specific language stimulation techniques when interacting with children in the classroom, such as event casts. (Chambers et al., 2010, p. 25) Study/Studies evaluating Intervention/Curriculum/Practice Curriculum/Program Assel et al. (2007); PCER (2008) Curriculum/Program PCER (2008) Let s Begin with the Letter People Let s Begin with the Letter People emphasizes early language and literacy development through play. In addition to classroom teaching, the program has a strong home/parent component. The curriculum is arranged in the following five themes: 1) All About Me, 2) Animals, Animals, and Animals, 3) Everyone Has Needs, 4) Getting Along with Others, and 5) Nature All Around Us. (Chambers et al., 2010) Curriculum/Program PCER (2008) 17

18 Name Description Intervention/Curriculum/Practice Literacy Express Project Approach Literacy Express is a preschool curriculum that is designed to promote children s emergent literacy skills. The curriculum is structured around thematic units that are sequenced in order of complexity. Each unit includes selected children s books that address theme-relevant vocabulary for small- and large-group reading activities. In addition, each thematic unit includes small-group activities, conducted three to four times a week, which provide homogeneous small groups of children with practice in the skills needed to develop oral language, phonological sensitivity, and print awareness. The large-group and extension activities provide opportunities for children to apply newly acquired skills in varied contexts. (Chambers et al., 2010, p. 27) Project Approach is a set of teaching strategies that enables teachers to guide children through in-depth investigations of real world topics. The curriculum is designed to use children s interests as the starting point for organizing and developing classroom learning activities. Three curriculum components address children s learning needs: spontaneous play, systematic instruction, and project work. A project is defined as an in-depth study of a real world topic that is worthy of children s attention and effort. Projects can be incorporated into an existing classroom instructional program and can extend over several days or weeks. The structural features of Project Approach include discussion, fieldwork, representation, investigation, and display. During the preliminary planning stage, the teacher selects the topic of stud (based primarily on classroom learning goals, children s interests, and the availability of local resources). The teacher then brainstorms his or her own experience, knowledge, and ideas and represents them in a topic web. This topic web is revised throughout the project and used for recording progress. In Project Approach classrooms, the daily schedule is structured so that children and teachers spend at least 45 to 60 minutes engaged in investigation and discovery, typically in small groups. (Chambers et al., 2010, p. 29) Study/Studies evaluating Intervention/Curriculum/Practice Curriculum/Program PCER (2008) Curriculum/Program PCER (2008) 18

19 Name Description Intervention/Curriculum/Practice Ready Set Leap! Waterford Early Reading Program Alphabetic Reading Program Ready, Set, Leap! is a comprehensive preschool curriculum, published by LeapFrog SchoolHouse, which combines literacyfocused instructional approaches with multisensory technology. The curriculum is structured around nine thematic units, each with detailed lesson plans for large- and small-group instruction, and ongoing assessment tools. The program stresses the importance of experiential learning, social and emotional development, teacher-child relationships, and home-school connections. The curriculum includes language and early literacy, mathematics, science, social studies, fine arts, health and safety, personal and social development, physical development, and technology applications. The language and literacy component emphasizes phonological awareness, alphabetic knowledge, print awareness, oral language development, reading aloud, and reading comprehension through story discussion. The technology is designed to provide thematic center-based activities that provide individualized feedback to students. There is also a component to encourage parent-child interactions and to forge strong home-school connections. (Chambers et al., 2010, p. 30) The Waterford Early Reading Program (Waterford) is an ICT integrated learning system that provides 15 minutes of daily computerized one-to-one learning activities for preschool children. It focuses on teaching children their letters, as well as developing phonological and phonemic awareness, story and print concepts, and language concepts. It gives teachers information on children s levels of skill, which they are expected to use to provide appropriate teaching outside of computer time. Developmentally appropriate books and videotapes are introduced in class and then sent home with children. (Chambers et al., 2010, p. 33). The Alphabetic Reading Program aimed to improve phonological awareness, letter knowledge, and writing. Phonological awareness training involved segmenting words into syllables and sub-syllables and retrieving initial sub-syllables. The program also focused on teaching etter-name and letter-sound correspondences using children s own names, stickers, magnetized letters, newspaper cuttings, etc. Study/Studies evaluating Intervention/Curriculum/Practice Curriculum/Program Abt Associates (2007) Curriculum/Program Abt Associates (2007) Specific Practice Aram (2006); Aram & Birron (2004) 19

20 Name Description Intervention/Curriculum/Practice Dialogic Reading HIPPY Program Head Start REDI Program Dialogic Reading is an emergent literacy intervention program developed by Whitehurst and his colleagues (1994). The program is an interactive story reading program aimed at improving the oral language and listening comprehension abilities of young children. Children in the Dialogic Reading program are encouraged to switch roles with their teacher to become the storyteller during small-group shared reading practice. The teacher assumes the role of active listener and questioner, helping children to improve their oral and language skills in the reading process. In a typical Dialogic Reading program, parents are also involved in the process by reading to their child daily using the same books that their child used during dialogic reading in class. (Chambers et al., 2010, p. 18). The HIPPY Program includes both reading and perceptual motor elements. Each day, mothers were to read to their children from one of the books and administered one set of activities. These activities ranged from a series of questions the mother was to ask the child, along with possible responses; connect the dot activities; identifying the appropriate object from a printed matrix (e.g., find the girl with the hat from a matrix of boys and girls with and without hats); and coloring activities. (Baker et al., 1988, p. 574). REDI (Research-based, Developmentally Informed) is an enrichment program that was integrated into regular Head Start centers that use High/Scope or Creative Curriculum. This program is designed to promote academic and social-emotional school readiness to preschoolers by training teachers using program-based strategies and techniques in their classrooms that combined Preschool PATHS and Dialogic Reading (Whitehurst, Arnold et al., 1994), a set of Sound Games (Adams et al., 1998), and print center activities, for emergent literacy skills. Teachers received a three-day intensive training prior to the intervention and a one-day followup training four months after the intervention. In addition, teachers received weekly mentoring support provided by REDI trainers. Parents were also provided with materials for home activities with their children. (Chambers et al., 2010, p. 31) Specific Practice Study/Studies evaluating Intervention/Curriculum/Practice Aram, 2006; Aram & Birron (2004); Arnold et al. (1994); Chow & McBride-Chang (2003); Chow et al. (2008); Crain-Thompson & Dale (1999); Cronan et al. (1996); Huebner (2000); Lonigan & Whitehurst (1998); Lonigan et al. (1999); Reese et al. (2010); Valdez-Menchaca & Whitehurst (1992); Wasik & Bond (2001); Wasik & Bond (2006); Whitehurst et al. (1988); Whitehurst et al. (1999) Curriculum/Program Baker et al. (1988) Curriculum/Program Bireman et al. (2008) 20

21 Name Description Intervention/Curriculum/Practice Dialogic Reading with Morphology Training In this program morphology training was added to dialogic reading practices. The morphology training involved focusing children s attention to morphosyllabic properties of language and to identify morphemes. Children were also provided with homophone training that focused on training children that the same sound might have different meanings. Focused Stimulation The Focused Stimulation program was from the Hanen Program that trains parents to: (a) follow the child s lead to establish a joint focus, (b) model language that is contingent on the child s focus (e.g., labels, expansions, comments) and (c) encourage the child s participation in conversation by promoting turn-taking. This program content was adapted to include three modifications consistent with a focused stimulation approach. First, mothers were taught to introduce specific target words during the second parent training session. Ten of the 20 selected words were randomly assigned to the target word condition by the investigators. Parents were given a list of the target words and instructed to use them in naturalistic routines. For example, if a target word was baby, the parent was instructed to model this word in the following manner in a joint action routine or game: baby. let s hug the baby, hug baby, you hug the baby. baby, etc. At no time was the child asked to repeat the word. In the third evening session, parents were trained to model the words in many different contexts, using different exemplars to express different intentions (e.g., request, comment). The parent s use of target words was reviewed during each evening session, and parents kept diaries of the child s imitative and spontaneous production of these and other words. Second, in the sixth evening session, parents were trained how to select additional lexical targets. Third, in the final evening session parents were taught to expand target words into two-word phrases and model word combinations. (Girolamettor et al., 1995, p. 43). 21 Study/Studies evaluating Intervention/Curriculum/Practice Chow et al. (2008) Girolametto et al. (1995)

22 Name Description Intervention/Curriculum/Practice Study/Studies evaluating Intervention/Curriculum/Practice Literacy Promotion Literacy Promotion involves training teacher in several areas that are thought to promote reading amongst children. This includes physical design of the classroom; effective book dis plays; importance of reading aloud to children; interactive techniques for reading aloud; environmental print; author, genre, and content themes created with the book collection; small-group lessons using teacher-made material based on books read; emergent writing or match-to-print opportunities; and literacy activity during play. McGill-Franzen et al. (1999) Elaborative Reminiscing The Elaborative Reminiscing practice is a set of guidelines for verbally interacting with children that are based on the same techniques employed in the dialogic reading intervention. This includes the use of open-ended questions, following the child s lead, expanding on the child s utterances, and linking the past event to other aspects of the child s experience. These practices are aimed to be used everyday. Specific Practice Reese et al. (2010) Interactive Child Centered Intervention Dialogic Reading with Sound Foundations Language stimulation provided speech pathologist. Stimulation focused on vocabulary size and two-three word utterances. The dialogic reading component was similar to that described earlier in this table. The Sound Foundations program is a phonemic awareness curriculum. Intervention Robertson & Weismer (1999) Composite Whitehurst et al. (1999) 0 22

23 Forsknings-review - Sprogpakken.dk Question 1 Synthesis of Research: Meta-analyses & Discussion Can a curriculum-based approach to early childcare produce results better than teaching adhering to a non-specific program? The aim of the first set of comparisons is to address whether curriculum/systematic approaches to early education are associated with better language and literacy skills compared to non-systematic approaches. The results of these studies are summarised in Tables 4-9. In all of these studies, the intervention comprises a systematic curriculum for teaching language and pre-literacy skills. The control group comprised of non-specific practices devised by individual teachers. It is important to note that these studies are evaluating a range of different curriculum/programs. These comparisons do not necessarily inform which specific practices are best for supporting early language and literacy skills in young children. However, by treating all different curriculum/programs as being representative of a systematic approach to improving language and literacy in young children the question we can examine is whether, overall, systematic/curriculum based approach is better, the same or worse than non-systematic/non-curriculum based approach. Receptive Vocabulary. The first set of results examined related to receptive vocabulary. Table 4 shows the individual effect sizes and 95% confidence interval for individual studies. At the study level, while all but one study favoured a curriculum approach, the effect sizes were not significantly different from zero. However, the average effect size computed using all studies was found to be.120 (a small effect size) which was statistically significant from zero (p =.036). This result indicates that regardless of the intervention used, overall, a curriculum based approach will is associated with a significant, albeit, small increase in receptive vocabulary scores. 23

24 Table 4. Individual and Weighted Averaged Effect Sizes (Cohen s d) Comparing Curriculum and Non-Curriculum Approaches on Improving Receptive Vocabulary a. Study Curriculum Evaluated Effect Standard Error Size b 95% Confidence Intervals for the Effect Size p-value Lower Limit Upper Limit PCER (2008) Bright Beginnings PCER (2008) Creative Curriculum PCER (2008) Creative Curriculum PCER (2008) Door to Discovery PCER (2008) Let s Begin with the Letter People PCER (2008) Project Approach Weighted Average * Notes: a All studies measured receptive vocabulary using the PPVT (see Appendix B for description of the test; b Positive values favour curriculum, negative values favour non-curriculum approach;*p <.05; **p <.001. Language: Expressive Vocabulary. Table 4 shows individual and a weighted average effect sizes for studies examining expressive vocabulary. In this table, two studies reported a statistically significant effect favouring a curriculum based approach and one favoured a non-curriculum based approach. The overall effect size was found to be.124 that was not statistically significant from zero (p =.231). In this case there was no difference between curriculum and individualised teaching practices. Table 5. Individual and Weighted averaged Effect Sizes (Cohen s d) Comparing Curriculum and Non-Curriculum Approaches on Improving Expressive Vocabulary. Study Curriculum Evaluated Effect Standard Size c Error 95% Confidence Intervals for the Effect Size Lower Limit Upper Limit p-value Abt Associates (2007) a Ready Set Leap! <.001** Building Early Language Abt Associates (2007) a and Literacy (BELL) Abt Associates (2007) a Breakthrough to Literacy <.001** Assel et al. (2007) b Doors to Discovery * Weighted Average Notes: a Expressive vocabulary measured using the Definitional Vocabulary subtest from the TOPEL; b Expressive vocabulary measured using the EVT (see Appendix B for description of the tests; c Positive values favour curriculum, negative values favour non-curriculum approach;*p <.05; **p <