At the time of this review, there are no available published research studies on The InvestiGator Club® Just for Threes 2018 Learning System (Just for Threes 2018). Research is needed in order to establish evidence for positive effects of Just for Threes 2018 on children's learning outcomes.

Approaches to Learning: Just for Threes 2018 consistently promotes research-based teaching practices to support children's approaches to learning, including emotional and behavioral self-regulation and executive functioning. For example, the Let's Investigate Teacher Guide offers guidance on classroom organization, such as sample whole-day and half-day schedules and multiple ways to support children during transitions throughout the day. The Research and Professional Guide describes how to establish positive rules and consistent routines. Learning experiences based on the curriculum's characters (e.g., Manny Salamander, Bruno Buzzbee) center around stories and discussions that foster the development of emotional, behavioral, and cognitive self-regulation skills. The Building Social and Emotional Skills Activity Guide provides additional guidance on supporting children as they learn to regulate their emotions. For example, it offers social coaching prompts (e.g., Validate children's emotions, follow with neutral words, and offer solutions, letting children choose the one that works for them). The daily schedule includes opportunities for children to choose learning centers that support their behavioral regulation (e.g., taking turns, following directions). A limitation is that, though learning centers allow for some open-ended exploration, there are limited opportunities for child-initiated play and activities based on children's interests.

Social and Emotional Development: Just for Threes 2018 consistently promotes research-based teaching practices in this domain. The Research and Professional Guide provides guidance focused on establishing an emotionally supportive environment in the "Social Emotional Development" and "Establishing a Community of Learners" sections. For example, the curriculum suggests teachers create a climate of kindness and generosity, speak respectfully to children, and respond to them with sensitivity and patience. The Building Social and Emotional Skills Activity Guide (part of the Social and Emotional Development Kit), as well as the units Marvelous Me! and Let's Investigate, include intentionally sequenced learning experiences that promote social and emotional learning and support teachers in using language to foster children's social and emotional development. Daily routines and activities, as described in the Teacher Guides, offer many formal and informal opportunities for children to practice social interaction and relationship skills with their teachers and other children (e.g., Opening Circle Time, Small Group, and Learning Centers).

Language and Communication: Just for Threes 2018 consistently promotes research-based teaching practices to support children's language and communication skills. Daily routines and activities (e.g., Opening Circle, Small Group, Learning Centers) include many ongoing opportunities for rich oral language experiences as well as formal and informal opportunities for children to engage in verbal interactions with adults and peers. For example, lessons in the Marvelous Me! unit provide prompts (e.g., What sounds do you think we will hear on our walk? Where should we go to hear lots of sounds?) that guide teachers on how to engage children in extended discourse. Whole-group literacy lessons offer daily opportunities for interactive read-alouds using dialogic reading, a research-based practice for promoting children's oral language development. To support children's vocabulary development, the curriculum provides guidance on how to use theme-related vocabulary throughout the day. In addition, Everyday Literacy and Small Group times incorporate learning experiences from the Extension Activities and Marvelous Me! unit which use the sounds of language to develop children's phonological awareness.

Literacy: The curriculum promotes research-based teaching practices to support learning in this domain. Opening Circle, Learning Centers, Everyday Literacy, as well as Small Group and Whole Group Literacy activities, provide varied and meaningful opportunities for children to discuss, use, and make print materials. For example, the curriculum offers activities such as Reading and Writing Learning Centers, shared reading of Flapboards and trade books, and dictation. Activity plans for read-alouds include strategies for developing critical literacy skills, such as asking questions about letters, words, signs, and labels; modeling reading conventions; and retelling to aid comprehension. However, the curriculum included less evidence for planning literacy experiences based on rich and engaging content or children's existing knowledge, skills, and interests. An additional limitation is that most of the curriculum's learning experiences that support alphabet knowledge are isolated activities rather than embedded in meaningful contexts.

Mathematics Development: The curriculum promotes research-based teaching practices to support children's development of mathematical concepts and skills. Lesson plans for Small Group and Whole Group (e.g., Extension Activities) include intentionally planned math learning activities. Quick Minutes, and Choices from the Let's Investigate Teacher Guide are embedded as Whole Group activities, which may also be used to incorporate learning about numbers throughout the day. The curriculum provides guidance on how to introduce children to key mathematical concepts and offers many opportunities to practice mathematical skills and concepts (e.g., Quick Minutes, Learning Centers). In addition, it promotes a mathematically-rich environment (e.g., blocks, manipulatives), and math vocabulary is introduced explicitly and utilized in suggested math learning activities. While some learning experiences offer opportunities for children to use math for a purpose (e.g., counting snacks, measuring the height of each plant), most math experiences do not involve everyday problems during routines and play or engage children in activities that promote inquiry and creative invention.

Scientific Reasoning: The curriculum promotes research-based teaching strategies to support children's development of scientific reasoning. Just for Threes 2018 provides hands-on science learning experiences through Science Center, Small Group, and Whole Group activities that facilitate the development of inquiry skills, such as making observations, asking questions, and gathering information. For example, the Just for Threes 2018 Teacher Guide weekly lesson planners include science learning experiences from the Let's Investigate Teacher Guide (e.g., Science Quick Minutes, Science Choices) as well as learning experiences from the Just for Threes 2018 Teacher Guide (e.g., Extension Activities, Marvelous Me! unit). Through the Let's Investigate unit, children learn a process for investigating—look and ask, try it, and try it again, think about it, and make meaning. Throughout science learning experiences, children are encouraged to document and share their findings (e.g., share verbally, draw a picture). A limitation is that many science activities, even within the Science Learning Center, have specific instructions for children to follow, leaving little room for teachers to build on children's previous experiences and interests or facilitate open-ended investigation.

Perceptual, Motor, and Physical Development: The curriculum promotes research-based teaching strategies to support children's development in this domain. The Research and Professional Guide provides guidance for creating safe indoor and outdoor areas that promote children's movement and physical activity. Curriculum resources (e.g., The Outdoor and Creative Play Learning Cards, More InvestiGator Club Songs, Chants, Rhymes and Games, Quick Minutes) describe activities that foster the development of locomotor and gross motor skills. The curriculum also supports fine motor development through daily experiences in the Learning Centers, such as Writing, Math, and Art. The Let's Investigate Teacher Guide offers some specific guidance for health and nutrition in the Daily Routines section, as do some lessons in the Just for Threes 2018 Teacher Guide. Even so, teachers may or may not choose to use Quick Minutes that focus on activities in this domain, and the curriculum does not discuss how to use the Outdoor and Creative Play Learning Cards. Thus, the frequency of moderate to vigorous activity and opportunities to practice new physical skills is unclear. In addition, the curriculum lacks guidance on how teachers can intentionally scaffold the development of children's physical skills (e.g., suggestions for modeling or specific feedback).

Scope: Just for Threes 2018 clearly identifies 10 developmental domains: Language Development, Literacy, Mathematics, Science, Creative Arts, Social and Emotional Development, Approaches to Learning, Physical and Mental Health, Social Studies, and Technology. The Just for Threes 2018 Teacher Guide provides guidance for daily lesson plans and learning activities to support children's development in these domains. Detailed guidance for some activities is found in the Let's Investigate Teacher Guide, Social and Emotional Development Kit, and Outdoor and Creative Play Cards.

Sequence: In some developmental domains, Just for Threes 2018 provides a sequence of learning experiences that progressively builds children's knowledge and skills as they move through the developmental progressions. For example, in the domains of Approaches to Learning, Social and Emotional Development, Language and Communication, and Literacy, the Let's Investigate and Just for Threes 2018 Teacher Guides describe a variety of learning experiences that build children's conceptual knowledge and skills over time. However, learning experiences in the domains of Mathematics, Scientific Reasoning, and Perceptual, Motor, and Physical Development do not appear to build on each other from less to more complex over time nor reflect children's developmental progressions. For example, in the domain of Mathematics Development, there is a clear progression in some skills but not others. In addition, the curriculum lacks guidance on how to individualize the sequence of learning experiences based on children's individual strengths and needs.

Alignment with the ELOF: A thorough review of all the curriculum materials in relation to the ELOF domains and sub-domains indicates Just for Threes 2018 is fully aligned with the ELOF. The learning experiences described in the Just for Threes 2018 and Let's Investigate Teacher Guides, Social and Emotional Development Kit, and Outdoor Creative Play and Learning Cards support children in each of the ELOF sub-domains. Additionally, learning centers (e.g., Reading, Math, Technology) provide opportunities for children to practice domain-specific skills.

Learning Goals: The curriculum specifies measurable, developmentally appropriate goals for children's learning and development. Within the Teacher Guides, learning goals are specified in relation to each of the Learning Centers and Small and Large Group activities. The learning activities support children in making progress toward these learning goals. However, the curriculum lacks guidance on how to use the learning goals with diverse children or how to adjust the learning goals to individualize learning experiences based on strengths and needs.

Ongoing Observation and Documentation: The Let's Investigate Teacher Guide includes specific guidance for teachers to observe, document, and reflect on children's development. It provides suggestions for observing, recording anecdotal notes, and collecting representations of children's learning in small-group, whole-group, and individual settings. The PreKindergarten Assessment and Intervention System includes authentic assessment tools (e.g., Anecdotal Notes and Narrative Progress forms) and performance assessment tools, such as Assessment Cards. In addition, the Let's Investigate Teacher Guide gives some direction on when to use the Assessment Cards. For example, "Do children attempt to use new vocabulary and grammar in speech, or do they need prompting? Use Assessment Card 6 to assess this skill and to implement intervention strategies." The curriculum provides some guidance in the form of reflective questions that assists teachers in using assessment to inform planning (e.g., What can I do each day to reinforce these skills? How can I meet with these few children on a regular basis to reinforce these skills?) However, this guidance is not embedded throughout all curriculum materials. The Just for Threes 2018 Teacher Guide and Social and Emotional Development Kit lack direction on how to observe, document, and reflect on children's development. An additional limitation is that there is no specific guidance on how to use assessment information to inform curriculum planning.

Standardized and Structured Assessment Instruments: Just for Threes 2018 encourages programs to use the publisher's structured assessment instrument (Assessment Cards) included in the PreKindergarten Assessment and Intervention System. The curriculum describes how assessment tools should be age-appropriate but does not discuss the importance of assessment instruments that are valid, reliable, or individually, linguistically, or culturally appropriate.

Communicating with Families: The Research and Professional Guide offers strategies for communicating with families (e.g., have an "open-door policy", weekly newsletters, and the Bruno Buzzbee Mail Poster). The curriculum provides Family Welcome Guides that include information on topics such as child development, the daily classroom routine, and the curriculum's characters. In addition, teachers are encouraged to gather information about the children from their families using the At-Enrollment Family Survey. The At-Enrollment Survey, family letters, and other materials are available in English and Spanish. However, the curriculum lacks guidance on how to communicate with parents and families in culturally and linguistically responsive ways.

Engaging Families: Just for Threes 2018 provides specific guidance on how to engage parents and families in program activities and how families can extend learning at home. For example, the Research and Professional Guide describes how to host a "Welcome to the Club Family Night," and the Let's Investigate Teacher Guide includes theme-based activities for "Family Investigation Nights" and "Investigation Celebrations." Additionally, the Research and Professional Guide offers a list of other ways to involve families, such as making a special snack with children. The curriculum includes some considerations on how to engage diverse parents and families. For example, the Research and Professional Guide suggests inviting parents to share their culture or ancestral heritage with the class. To extend learning at home, each unit includes a small take-home book related to the theme. Both the take-home books and instructions are provided in English and Spanish. Even so, there is limited consideration embedded within the curriculum for how to engage parents from diverse cultures, parents who speak languages other than English and Spanish, or parents who have disabilities or other special needs.

Professional Development: The publisher provides online and onsite options for initial training and ongoing professional development opportunities. The curriculum includes a one-hour Just for Threes 2018 Implementation Training webinar as well as materials for programs to conduct a one- or two-day on-site implementation training. The Facilitators' Implementation Guide notes that the training can be self-guided or led by an outside facilitator. The curriculum developer offers a large number of ongoing professional development opportunities for an additional cost. Examples of topics include, but are not limited to, Developmentally Effective Approaches to Teaching and Learning, Center-Based Learning for the Preschooler, and Literacy and Learning for English Language Learners (ELLs). In addition, the website for teachers includes a number of free webinars and bulletins that provide research-based information and practices on specific topics (e.g., Young Children and the Environment: Building a Connection, Inspiring Good Behavior). Upon request, the publisher offers customized workshops. 

Curriculum Materials to Support Implementation: Just for Threes 2018 provides materials to support implementation, such as the Research and Professional Guide, Just for Threes 2018 Teacher Guide, Let's Investigate Teacher Guide, and the Implementation Facilitator Guide, Participant Workbook, and DVD. The Research and Professional Guide provides general information on program philosophy, classroom environment and management, the role of the family, and cultural and linguistic diversity. The Just for Threes 2018 Teacher Guide offers 30 weekly plans for Opening Circle, Everyday Literacy, Small and Whole Group, and Closing Circle Time, as well as extension activities; songs, chants, rhymes, and games; and book suggestions. The weekly plans reference lesson plans from the Let's Investigate Teacher Guide, and lesson plans describe how to implement learning experiences, list required materials, and articulate teaching practices. The Implementation Facilitator Guide, Participant Workbooks, and DVD help programs organize their implementation efforts. A limitation is that the Implementation Facilitator Guide, and Participant Workbooks do not address implementation of Just for Threes 2018; they specifically reference the materials in InvestiGator PreK.

• Fidelity Tool: Just for Threes 2018 offers the InvestiGator Club Monitoring Tool, which can be used to support teacher success and continued professional development and to assess fidelity of implementation. The tool guides observation in different areas, such as classroom environment, child assessment, daily routines, and language and literacy instruction.

Active Exploration: The Research and Professional Guide describes the importance of hands-on exploration for children's learning (e.g., "Children need a learning environment that allows them to initiate active exploration with materials and make choices about their own activities). The Let's Investigate Teacher Guide describes a variety of Learning Centers (e.g., Science, Art, Sand and Water) with open-ended materials that promote hands-on exploration. A limitation of the learning centers and activities described in the Teacher Guides is that they do not provide children with ample opportunities to actively engage in open-ended, hands-on exploration. All activities, including Learning Centers and Investigation Station, are structured and give specific directions about what children are to do with the materials. Children have little opportunity to engage with materials in open-ended ways or create and experiment with materials.

Interactions That Extend Children's Learning: The Just for Threes 2018 and Let's Investigate Teacher Guides, as well as the Social and Emotional Development Kit, offer specific guidance and examples of ways to use teacher-child interactions to extend children's learning throughout the day. Lesson plans for Opening Circle Time, Choices, and Small Group activities include opportunities for brainstorming and discussions. They use open-ended questions as prompts. For example, during Small Group, children investigate their shadows by moving their bodies closer and further to the wall, and teachers ask questions such as, "How does your shadow change?" In addition, scripts for Flapboarding and other structured activities provide prompts to extend children's exploration, thinking, and communication (e.g., encourage children to feel the objects and talk about what they notice. Help them sort and group items that feel the same. As children sort, ask, "Why do you think this one goes in this pile?").

Individualization: The Research and Professional Guide provides general guidance on how to individualize learning experiences for all children. Additionally, the Let's Investigate Teacher Guide offers more specific supports for children who have disabilities, suspected delays, or other special needs, as well as children who are DLLs, using callout boxes (e.g., Differentiation: Inclusion, ELL) in the lesson plan margins. For example, to support DLLs in a matching activity, the curriculum suggests the teacher give step-by-step directions by pointing to a picture on the list and saying, "Find this [block] in the basket; put it on your list." The Marvelous Me! unit offers a few ELL callout boxes, as well (e.g., encourage ELLs to use the four key "taste" words and to add to their descriptive language with gestures). Even so, the Just for Threes 2018 Teacher Guide, Social and Emotional Development Kit, and Outdoor Creative Play and Learning Cards lack guidance on how to individualize learning experiences for children with disabilities, suspected delays, or other special needs. Overall, the curriculum lacks guidance on how to individualize learning experiences for children from diverse cultural backgrounds.

Environment: Just for Threes 2018 offers specific guidance on how to design a well-organized, engaging indoor environment and some guidance for setting up the outdoor environment. The Research and Professional Guide describes how to select and arrange furnishings, display children's work, store materials, and establish learning centers with materials to promote flexible learning opportunities. It also outlines principles for designing the outdoor environment (e.g., include both structure and exploration, promote large-group, small-group, and independent play). The Research and Professional Guide provides some guidance on ensuring children's home languages are included in the physical environment. In addition, the Research and Professional Guide and Let's Investigate Teacher Guide provide limited direction on creating an accessible physical environment for children with specific disabilities or special needs. However, the curriculum lacks guidance on how to include children's home language and cultures into the physical environment. Though the curriculum offers some guidance on representing cultural diversity in the environment, it does not offer ways to ensure the environment represents the cultures and ethnicities of the children and families.

Learning Materials: Just for Threes 2018 includes specific lists of learning materials for Learning Centers and learning experiences. The Research and Professional Guide presents a list of suggested materials for each of the Learning Centers and specific guidance for organizing and labeling materials (e.g., "Label each container with both a word and a picture describing the contents."). The lessons in the Teacher Guides list learning materials to be used in specific learning activities and instructions for their use. The curriculum provides some guidance for ensuring the learning materials meet the individual needs of children with disabilities or other special needs. For example, "Differentiation: Inclusion" callout boxes may describe ways to adapt materials for accessibility, and the Social and Emotional Development Kit and Outdoor Creative Play and Learning Cards offer some suggestions as well (e.g., providing an adaptive ball or slightly deflated ball can assist children with limited physical abilities). However, the curriculum lacks guidance on how to select learning materials that authentically represent the cultures, ethnicities, and home languages of children in the program. The Research and Professional Guide offers specific guidance on how to select learning materials that represent the home languages of children in the program. However, the curriculum lacks guidance on how to select learning materials that authentically represent the cultures and ethnicities of children in the program. 

Schedule and Routines: The curriculum provides guidance on how to establish a daily schedule and developmentally appropriate routines. The Let's Investigate Teacher Guide offers sample daily schedules for half- and whole-day programs. This Teacher Guide also describes daily routines (e.g., Start Your Day, Health, Transitions) as well as "Explicit Lessons" (e.g., Opening Circle, Everyday Literacy, Small Group) that are embedded across the weekly plans in Just for Threes 2018. The sample daily schedules show times designated for Clean Up, Transitions, Outdoor Play (for whole-day programs), Snack, and Bathroom. However, the Just for Threes 2018 Teacher Guide does not include these samples in the Lesson Planner. In addition, the curriculum lacks discussion on how to adjust schedules and routines based on children's needs and backgrounds.

Interactions: The curriculum provides limited guidance for working with culturally and linguistically diverse families and children. For example, the Social and Emotional Development Kit Activity Guide reminds teachers to make sure children are aware of the other perspectives of children from diverse backgrounds and cultures. However, the curriculum lacks further guidance on how to engage in culturally responsive interactions with children and families.

Learning Experiences: Just for Threes 2018 lacks guidance on how to provide learning experiences that build on children's and families' traditions, cultures, values, and beliefs. One of the curriculum's characters (JT Gator) is fascinated by geography, culture, and travel, knows a lot about traditions and customs of people around the world and acts as a gateway to experiences that relate to diverse cultures. However, the learning experiences set around his character do not build on the cultures or languages of children in the group.

Learning Environment: The curriculum suggests some children's books (e.g., Be My Neighbor, Abuela) and includes some materials (e.g., Vocabulary and Oral Language Cards) that reflect children and families from diverse cultures and ethnicities. It provides general guidance on selecting materials that reflect children's cultures and ethnicities. For example, the Research and Professional Guide recommends teachers "display pictures of different families in communities around the world," and each investigation includes "multicultural tales." 

Scaffolding Strategies: The curriculum provides some specific guidance on how to support the development and learning of children who are DLLs. Some lessons in the Let's Investigate Teacher Guide and Marvelous Me! unit include ELL callout boxes that identify strategies specific to individual learning activities (e.g., an English-speaking partner can lead a learner of English in doing each movement; use the Rosalita Word poster to support words in print). However, the guidance on how to scaffold the development and learning of children who are DLLs is not embedded in parts of Just for Threes 2018 Teacher Guide, (e.g., Extension Activities) Social and Emotional Development Kit, and Outdoor Creative Play and Learning Cards. In addition, the Research and Professional Guide describes daily support, such as using vocal expression, gestures, and visual supports. 

Home and Tribal Languages: The curriculum provides general guidance on how to incorporate children's home languages into the learning environment. The Research and Professional Guide offers suggestions such as using functional labeling for objects in the classroom and having many bilingual books. The curriculum provides some materials (e.g., Flapboard stories) in English and Spanish and the Teacher Guides identify some ways to incorporate English and Spanish (e.g., introduce the Word of the Week and record the day of the week in Spanish and English). However, Just for Threes 2018 lacks guidance on how to authentically incorporate children's home languages into learning experiences and daily interactions. Tribal languages are not addressed.

Teaching Practices and Interventions: Some of the materials in the Just for Threes 2018 curriculum (also included as part of the InvestiGator PreK curriculum) provide guidance on how to embed teaching practices and other interventions in daily routines and activities to support the learning of children with disabilities, suspected delays, or other special needs. The Let's Investigate Teacher Guide includes "Differentiation" and "Differentiation: Inclusion" callout boxes that describe ways to individualize instruction and scaffold learning for children who have special needs. For example, it suggests that if a child has difficulty holding or manipulating a marker or pencil, offer hand-over-hand assistance; or if children are language-delayed, ask simple, specific questions to help them tell about themselves. In addition, the Outdoor Creative Play and Learning Cards offer inclusion prompts for each activity. However, lessons in the Just for Threes 2018 Teacher Guide (e.g., Marvelous Me! unit, Extension Activities) do not provide teaching practices and other interventions to support children with disabilities, suspected delays, or other disabilities.

Learning Environment: Just for Threes 2018 provides specific guidance in some of the curriculum materials to ensure the physical environment and learning materials are accessible to children with disabilities, suspected delays, or other special needs. The Research and Professional Guide gives a few examples of modifications to the physical environment. The "Differentiation" and "Differentiation: Inclusion" callout boxes in the Let's Investigate Teacher Guide include specific suggestions for how teachers may need to add or modify learning materials to meet individual children's needs. However, the activities within the Just for Threes 2018 Teacher Guide and Social and Emotional Development Kit lack guidance to ensure that the physical learning environment and learning materials are accessible to children with disabilities, suspected delays, or other special needs.

Individualization Based on Interests: Just for Threes 2018 describes Learning Centers as child-directed activities that encourage children to explore areas of interest. However, the curriculum does not offer guidance on how to plan learning experiences that build on individual children's interests. Learning experiences (including Learning Centers) are pre-planned, without direction on how to modify them based on individual children's interests.

Individualization Based on Strengths and Needs: The curriculum provides some support on how to make learning experiences responsive to individual strengths and needs. The Research and Professional Guide offers general guidance, such as asking teachers to reflect on what skills are the most challenging for children to master and what might be done to reinforce those skills. The Let's Investigate Teacher Guide includes some specific scaffolding suggestions for children at different developmental levels through "Differentiation" callout boxes. For example, in a gardening activity, children at more advanced levels of development are encouraged to try writing the name of their plant on signs using a word list as a model. However, the Marvelous Me! unit and other Just for Threes 2018 materials lack guidance on how to make learning experiences responsive to individual strengths and needs.