{"h1":"MacArthur–Bates Communicative Development Inventories (CDI)","faq":[{"a":"The parent or main caregiver completes it, because you see your child communicate across many everyday moments. A clinician then interprets it alongside their own observations.","q":"Who fills in the CDI — the parent or the clinician?"},{"a":"No. The CDI is a screening and research tool, not a diagnosis. A lower score simply suggests it is worth looking more closely with a qualified professional.","q":"Does a low CDI score mean my child has a disorder?"},{"a":"It is generally used from around 8 months to 3 years, with different forms suited to younger infants and older toddlers.","q":"At what age is the CDI used?"}],"lang":"en","slug":"what-is-the-macarthur-bates-communicative-development-inventories-cdi-and-what-does-it-assess","title":"What is the MacArthur–Bates Communicative Development Inventories (CDI)?","entity":{"key":"cdi","kind":"instrument","name":"MacArthur–Bates Communicative Development Inventories","slug":"cdi"},"lenses":[{"kind":"stakeholder","label":"Parent","value":"parent"},{"kind":"intent","label":"Definition","value":"definition"},{"kind":"lifecycle","label":"Measure","value":"measure"},{"kind":"route","label":"Screen","value":"screen"},{"kind":"empowerment","label":"Early Clarity","value":"early_clarity"}],"parent":{"key":"assessments","label":"Assessments"},"related":[{"lang":"en","slug":"should-my-child-have-a-cdi-assessment-and-what-does-it-involve","title":"Should My Child Have a CDI Assessment?"},{"lang":"en","slug":"when-is-the-cdi-indicated-and-what-are-its-strengths-and-limits-in-early-childhood","title":"When the CDI Is Indicated: Strengths and Limits in Early Childhood"},{"lang":"en","slug":"which-standardised-instruments-assess-the-communication-developmental-domain-in-young-children","title":"Standardised instruments for the Communication domain (ICF d3)"},{"lang":"en","slug":"how-does-the-cdi-compare-with-the-abilityscore-developmental-assessment","title":"How does the CDI compare with the AbilityScore developmental assessment?"},{"lang":"en","slug":"at-what-age-is-the-cdi-developmental-assessment-used-for-a-child","title":"At What Age Is the CDI Used for a Child?"},{"lang":"en","slug":"how-is-developmental-age-assessed-for-the-communication-domain","title":"How is developmental age assessed for the Communication domain?"}],"summary":"The MacArthur–Bates Communicative Development Inventories (CDI) are parent-report questionnaires that measure a young child's early communication — typically from around 8 months to 3 years. Because parents complete them from everyday life, they capture real-world skills: words understood, words said, gestures, and early word combinations. The CDI is a screening and research tool, not a diagnosis; a low score is an invitation to look more closely with a professional.","answer_md":"*A simple checklist a parent fills in — turning what you already notice about your child's words and gestures into a clear picture of early communication.*\n\n## In short\nThe **MacArthur–Bates Communicative Development Inventories (CDI)** are a well-established set of parent-report questionnaires that measure a young child's early language and communication. Because you, the parent, complete them based on what your child does in everyday life, the CDI captures real-world communication rather than how a child behaves in an unfamiliar room. They are widely used from around 8 months to 3 years to track words a child understands, words they say, gestures, and the first steps of sentence-building.\n\n## What the CDI assesses\nThe CDI comes in forms suited to different ages, and together they look at several threads of early communication:\n\n- **Words understood (receptive vocabulary)** — the words your child seems to recognise, even before they can say them.\n- **Words said (expressive vocabulary)** — the words your child actually uses.\n- **Gestures and actions** — pointing, waving, showing, and play gestures that are the foundation of communication before speech.\n- **Early grammar** — for older toddlers, how words begin to combine into short phrases and sentences.\n\nBecause parents see their child across many natural moments — meals, play, bath time — the CDI is considered a reliable, low-stress way to gather rich information. It is a **screening and research-supported tool**, not a stand-alone diagnosis. A score below the typical range is best understood as an invitation to look more closely with a professional, not a verdict.\n\n## When it helps\nThe CDI is especially useful when a parent or clinician wants to understand a late talker, track progress over time, or add a parent's everyday observations to a fuller developmental review. It works alongside — never instead of — a clinician's direct assessment of how a child listens, plays and communicates.\n\n## The Pinnacle way\nThis is general information, not a diagnosis — a clinical [AbilityScore®](/ask/what-is-the-abilityscore-and-how-is-it-calculated) and any diagnosis are formed only at a Pinnacle Blooms Network centre, under qualified clinician care, never from a single form. Our team may use parent-report tools like the [CDI](/cdi) together with structured observation, then shape an individualised plan that can draw on [speech therapy](/speech-therapy) where it helps your child flourish.\n\n## Trusted sources\nASHA guidance on early language development and parent-report measures; CDC developmental milestone resources on communication; the WHO Nurturing Care Framework on early childhood communication and learning.\n\n**Next step —** If you'd like to understand your child's early words and gestures, book a developmental review where a clinician can combine your everyday observations with a careful look at how your child communicates.","canonical":"https://pinnacleblooms.org/ask/what-is-the-macarthur-bates-communicative-development-inventories-cdi-and-what-does-it-assess","editorial":{"reviewed_at":"2026-06-11T20:12:18.613642+00:00","reviewed_by":null,"developed_by":"SETU Consortium · Pinnacle Blooms Network"},"alternates":[{"href":"https://pinnacleblooms.org/ask/what-is-the-macarthur-bates-communicative-development-inventories-cdi-and-what-does-it-assess","lang":"en","indexable":true}],"dimensions":[{"key":"assessments","label":"Assessments"}],"meta_title":"What Is the CDI (MacArthur–Bates)?","meta_robots":"index, follow, max-image-preview:large","everyday_tip":"Keep a casual note of new words and gestures your child uses each week — it sharpens what you'd capture on a tool like the CDI and gives a clinician a richer, real-life picture.","published_at":"2026-06-10T14:16:00.221239+00:00","reading_paths":[{"key":"understand","items":[{"lang":"en","slug":"at-what-age-is-the-cdi-developmental-assessment-used-for-a-child","title":"At What Age Is the CDI Used for a Child?","reason":"Linked from this answer"}],"label":"Understand the subject","total":1},{"key":"assess","items":[{"lang":"en","slug":"should-my-child-have-a-cdi-assessment-and-what-does-it-involve","title":"Should My Child Have a CDI Assessment?","reason":"Linked from this answer"},{"lang":"en","slug":"when-is-the-cdi-indicated-and-what-are-its-strengths-and-limits-in-early-childhood","title":"When the CDI Is Indicated: Strengths and Limits in Early Childhood","reason":"Linked from this answer"},{"lang":"en","slug":"how-does-the-cdi-compare-with-the-abilityscore-developmental-assessment","title":"How does the CDI compare with the AbilityScore developmental assessment?","reason":"Linked from this answer"},{"lang":"en","slug":"which-standardised-instruments-assess-the-communication-developmental-domain-in-young-children","title":"Standardised instruments for the Communication domain (ICF d3)","reason":"Linked from this answer"},{"lang":"en","slug":"how-is-developmental-age-assessed-for-the-communication-domain","title":"How is developmental age assessed for the Communication domain?","reason":"Linked from this answer"}],"label":"Understand assessment","total":5}],"what_to_watch":"Few or no words said by 18 months, limited understanding of everyday words, little use of gestures like pointing or waving, or words not yet combining into short phrases by around 2 years — worth a closer look with a professional.","authority_links":[{"url":"https://www.asha.org/public/speech/development/","label":"ASHA — early speech and language development"},{"url":"https://www.cdc.gov/child-development","label":"CDC — developmental milestones"},{"url":"https://nurturing-care.org/","label":"WHO Nurturing Care Framework"}],"last_reviewed_at":"2026-06-10T14:16:00.221239+00:00","meta_description":"The MacArthur–Bates CDI is a parent-report tool measuring young children's early words, gestures and sentences. Learn what it assesses and when it helps.","related_materials":[],"related_techniques":[]}