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Clausal Density Calculator.

Total clauses, total utterances, and the clauses-per-utterance ratio from a single pasted transcript. The calculator detects subordinate clauses with a heuristic over standard English subordinators and reports the developmental band against Loban (1976) and Nippold (2009) reference values — instantly, in your browser.

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Validated2026-04-08
CitableMethods and citation included

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Paste your language sample

One utterance per line. The calculator counts main and subordinate clauses, then reports the clauses-per-utterance ratio (clausal density) — instantly, in your browser.

Paste a transcript above to compute total utterances, total clauses, and clausal density (clauses per utterance).

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When to use

  • Computing clausal density from a transcribed language sample
  • Tracking syntactic complexity growth across therapy sessions
  • Comparing a school-age child against Loban (1976) or Nippold (2009) reference bands
  • Reporting a syntactic-complexity metric alongside MLU in an evaluation
  • Teaching graduate SLP students why MLU loses sensitivity above age 5
  • Spot-checking a transcript for embedded subordinate clauses

Do not use for

  • Diagnosing developmental language disorder from CD alone — combine with MLU, PGU, and lexical diversity
  • Reporting CD as a forensic-grade clause count — the heuristic is approximate
  • Comparing CD across different sampling contexts without context-matched norms
  • Evaluating preschoolers below age 5 — MLU is more sensitive at that age
  • Trusting the count without reviewing the per-utterance breakdown

CD complements MLU; it does not replace it

MLU is most sensitive in preschoolers; CD is most sensitive once children start embedding clauses around age 5. Report both for school-age clients.

Always review the per-utterance breakdown

The heuristic will mis-classify some utterances. Skim the breakdown, find the mis-counts, and adjust manually before writing the result into an evaluation.

Zero-relatives are invisible

"The boy I saw was tall" contains a zero-relative ("[that] I saw") that the heuristic cannot detect. If your client uses zero-relatives, manually bump the count or note the under-estimate in your report.

Context shapes CD

Conversational samples produce lower CD than narrative samples; expository samples produce the highest CD of all. Match the sampling context to the reference data when interpreting the band.

CD rises into adolescence

Unlike MLU, CD does not plateau in elementary school. Nippold (2009) shows CD continues to rise through age 17, especially in formal genres. Use CD when you need a measure that stays informative for older school-age clients.

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Method

Utterances are split with the shared SLP utterance parser (src/lib/slp/utterance-parser.ts) and tokenised with lowercase + leading/trailing punctuation stripped. Each non-empty utterance contributes one main clause. The detector walks tokens after the first token; each token that matches the subordinator list (because, when, while, if, although, since, before, after, until, that, who, whom, whose, which, where, why, how, what, as, …) adds one subordinate clause. Clausal density = total clauses / total utterances. Developmental bands follow Loban (1976) and Nippold (2009) reference values.

2

Validated

Last validated 2026-04-08. Calculations are designed for planning and documentation support; verify procurement decisions against manufacturer specifications or institutional SOPs.

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How to cite

How to Cite

ConductScience Clausal Density Calculator (v1.0). ConductScience, Inc. 2026. Available at: https://conductscience.com/tools/clausal-density-calculator

Loban W. Language Development: Kindergarten through Grade Twelve. National Council of Teachers of English; 1976. Research Report No. 18.

Nippold MA. Language Sampling with Adolescents: Implications for Intervention. Plural Publishing; 2009.

Brown R. A First Language: The Early Stages. Harvard University Press; 1973.

Hunt KW. Grammatical Structures Written at Three Grade Levels. National Council of Teachers of English; 1965. Research Report No. 3.

What Is Clausal Density?

Clausal density (CD) is the ratio of total clauses to total utterances (or T-units) in a transcribed language sample. A clause is a syntactic unit with a subject and a predicate; a main clause stands alone, and a subordinate clause is embedded inside another clause.

Why it matters. Two children can produce equally long utterances but show very different syntactic complexity. "I went to the park and I played and I came home" (3 main clauses, no subordination, CD = 1.0 if we treat each conjunct as a separate utterance) is structurally very different from "I went to the park because my friend asked me" (1 main + 1 subordinate, CD = 2.0). MLU cannot tell these apart; CD can.
When CD becomes useful. Below age 5, children produce mostly simple sentences and CD hovers near 1.0; MLU is the more sensitive measure. Above age 5, children begin to embed subordinate clauses, and CD rises through adolescence. By age 12, typical conversational CD is around 1.5 (Loban 1976; Nippold 2009).

How This Calculator Works

Paste your language sample into the textarea, one utterance per line. The calculator:

  • Splits the sample into utterances using the shared SLP utterance parser (newlines first, sentence-ending punctuation as a fallback).
  • Tokenises each utterance: lowercases, strips leading/trailing punctuation.
  • Counts one main clause per non-empty utterance.
  • Walks through the tokens after the first one and adds one subordinate clause for every token that matches the subordinator list (because, when, while, that, who, which, …).
  • Reports total utterances, total clauses, the clausal density ratio, the developmental band the ratio falls into, and a per-utterance breakdown so you can spot mis-classifications.

The heuristic is conservative — it does not handle zero-relatives, and it may over-count subordinators in fixed phrases. Treat the result as a screening number, not a definitive count.

Developmental Reference Bands

Below age 5 (CD < 1.10). Children at this stage produce mostly simple sentences. Subordinate clauses are rare. MLU is the more sensitive measure of expressive language at this age.
Ages 5-8 (1.10 ≤\leq CD < 1.30). Children begin embedding adverbial clauses ("because", "when") and complement clauses ("that"). CD starts to rise.
Ages 8-12 (1.30 ≤\leq CD < 1.50). Relative clauses, wh-complements, and multiple subordinators per utterance become common. CD continues to rise.
Age 12+ (CD ≥\geq 1.50). Adolescents and adults produce dense subordination, especially in expository and persuasive language. CD plateaus around 1.6-1.8 in conversational samples and can rise above 2.0 in formal narrative or expository samples.

These bands are rough guides drawn from Loban (1976) and Nippold (2009). They are not diagnostic cut-offs — interpret CD alongside MLU, PGU, and lexical diversity, and against context-matched norms when possible.

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Next steps

Protocol

MLU Calculator — compute MLU-morphemes from the same transcript

Reference protocol for the next planning step.

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Lexical Diversity Calculator — TTR + NDW from the same transcript

Reference protocol for the next planning step.

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PGU Calculator — percentage of grammatical utterances

Reference protocol for the next planning step.

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Brown's Stages Lookup — map MLU to grammatical milestones

Reference protocol for the next planning step.

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