What Is the Index of Productive Syntax?
The Index of Productive Syntax (IPSyn) is Hollis Scarborough's (1990) checklist of 56 grammatical structures that map the breadth of a child's expressive-syntax repertoire. It is one of the three most-cited language sample analysis (LSA) procedures alongside MLU and Developmental Sentence Scoring (DSS), and remains the standard tool for documenting expressive-syntax growth in school-age children with developmental language disorder.
Why it matters. Unlike MLU (which measures average sentence length) or DSS (which weights structures within a sentence), IPSyn enumerates each grammatical structure as a distinct yes/no/two-instance count. A child whose MLU and DSS are in the typical range can still earn a low IPSyn if they routinely use the same handful of structures and never produce, say, perfect aspect, relative clauses, or tag questions. IPSyn surfaces those breadth-of-structure gaps that simpler metrics miss.
How it is computed. Collect 100 consecutive intelligible spontaneous utterances. For each of the 56 items, search the transcript for instances. Score 0 (none), 1 (one instance), or 2 (two distinct instances using different lexical items). Sum the 56 item scores for the IPSyn total (max 112). Sum within each of the four subscales (Noun Phrase, Verb Phrase, Question/Negation, Sentence Structure) for the per-subscale subtotals.
The Four IPSyn Subscales
IPSyn organises the 56 items into four structurally coherent subscales drawn from the original Scarborough (1990) coding manual. Each subscale captures a different slice of grammatical development:
- Noun Phrase (NP) — 19 items, max 38 points. Covers proper and common nouns, modifiers, articles, pronouns (personal, reflexive, indefinite, demonstrative), plural and possessive morphology, two- and three-word noun phrases, conjoined NPs, and noun phrases modified by relative clauses. Sensitive to early lexical development and to the transition from telegraphic to fully elaborated noun phrases.
- Verb Phrase (VP) — 19 items, max 38 points. Covers main verbs, copulas, auxiliaries, particles and prepositions, third-person singular -s, regular and irregular past, modals, perfect aspect, passive voice, bitransitive predicates, adverbs, and contraction. Sensitive to tense/aspect mastery and to modal/auxiliary system development.
- Question / Negation (QN) — 9 items, max 18 points. Covers negative words, wh-question words, yes/no question intonation, copula and auxiliary negation, wh-questions with inversion, yes/no questions with inversion, tag questions, wh + modal questions, and negation with modals. Captures the development of clause-level operators that often lag in clinical populations.
- Sentence Structure (SS) — 9 items, max 18 points. Covers two-word combinations, basic SV and VO patterns, full SVO sentences, conjoined clauses, infinitive complements, adverbial subordinate clauses, relative or sentential complements, and dative shift. The most useful subscale for tracking emergent complex syntax in school-age intervention.
The four subscale subtotals plus the IPSyn total form the standard reporting block in an LSA evaluation report.
Scoring Rules — 0, 1, or 2
Each of the 56 IPSyn items is scored on a 3-point scale that reflects productivity, not frequency:
- 0 points — no clear instance of the structure appears in the 100-utterance sample.
- 1 point — one clear, productive instance appears.
- 2 points — at least two distinct instances appear, where "distinct" means the child used the structure with two different lexical items or surface forms.
Two instances of the same memorised phrase do not earn 2 points. For example, the past-tense -ed item earns 2 points if the child says "walked" and "jumped" but only 1 point if they say "walked" twice. The two-instance rule is the fundamental productivity check that makes IPSyn an index of *productive* syntax rather than a frequency count.
Echoed and imitated utterances are excluded from the sample before scoring. Frozen routines ("I love you", "no way") generally do not earn credit because they do not show productive grammatical control. When in doubt about a borderline instance, follow the scoring rule used in Pavelko, Owens, Ireland & Hahs-Vaughn (2016) — score conservatively and document the decision in the evaluation notes.
How This Calculator Works
Paste your 100 consecutive utterances into the textarea (one per line) and pick a subscale tab — Noun Phrase, Verb Phrase, Question/Negation, or Sentence Structure. Each item shows a row with its IPSyn code, label, and a one-line descriptor. Tap 0, 1, or 2 to record the score for that item; tap a different number to change it.
- The four metric cards at the top track the live IPSyn total (out of 112), the number of items at full credit (2 / 2), the parsed utterance count, and the total word count.
- The subscale subtotal grid below the metric cards shows each subscale running total against its maximum (NP / VP max 38, QN / SS max 18).
- If your sample is below the 100-utterance Scarborough minimum, the calculator displays an amber warning so you do not accidentally compare an under-sized sample against published norms.
- The calculator never sends your data anywhere. The transcript and the score map live in the page state and disappear when you close the tab.
You can switch subscales freely without losing scores from another subscale — every item is keyed by its IPSyn code and persists for the session.
