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DSS – Developmental Sentence Scoring

Status: Current

Purpose

Assigns point values to utterances based on grammatical complexity, using a configurable rule file that defines pattern-matching rules for morphosyntactic categories. DSS is a clinical tool developed by Laura Lee and Susan Canter for evaluating children’s grammatical development by scoring complete sentences on eight grammatical categories.

Scoring requires a %mor dependent tier on each utterance. Utterances without %mor are silently skipped.

See the CLAN manual for the original DSS command specification and the full rule set.

Usage

chatter clan dss --speaker CHI file.cha
chatter clan dss --rules english.scr file.cha
chatter clan dss --max-utterances 100 file.cha
chatter clan dss --format json file.cha

Options

OptionDescription
--speaker <CODE>Include speaker
--exclude-speaker <CODE>Exclude speaker
--rules <PATH>Custom DSS rules file (.scr)
--max-utterances <N>Maximum utterances to score (default: 50)
--format <FMT>Output format: text, json, csv, clan

Scoring Categories

DSS scores utterances on eight grammatical categories:

  1. Indefinite pronouns / noun modifiers (it, this, that)
  2. Personal pronouns (I, me, my, mine, you, your)
  3. Main verbs (uninflected, copula, auxiliary)
  4. Secondary verbs (non-finite: infinitives, gerunds, participles)
  5. Negation (no, not, can’t, don’t)
  6. Conjunctions (and, but, or, if, because)
  7. Interrogative reversals (is he, can you, do they)
  8. Wh-questions (who, what, where, when, why, how)

Each category earns 1-8 points based on developmental complexity. A sentence point is awarded if the utterance is a complete grammatical sentence.

Algorithm

  1. Parse each utterance’s %mor tier for POS-tagged morphemes
  2. Match morpheme patterns against category rules
  3. For each category, award points for the highest-scoring matched pattern
  4. Award sentence point for complete sentences (heuristic: subject + verb POS)
  5. Sum across categories + sentence point = utterance score
  6. DSS = mean score across scored utterances

Output

Per-speaker DSS total with per-category breakdown and per-utterance scores.

Differences from CLAN

Built-in rules

The default rules are a simplified subset of the canonical DSS rule set (10 categories). For full clinical scoring, supply a complete .scr rules file via --rules. When a rules file is not provided, DSS produces approximate scores suitable for screening but not clinical reporting.

Sentence-point assignment

Uses a heuristic (presence of subject + verb POS tags in %mor) rather than full syntactic analysis. This may under-award sentence points for syntactically complex but structurally unusual utterances.

Maximum utterances

Defaults to 50 per speaker (configurable via --max-utterances). CLAN also defaults to 50 but the implementation differs in how utterances are selected when the sample exceeds the maximum.

Output formats

Supports text, JSON, and CSV. CLAN produces text only.

Golden test parity

Verified against CLAN C binary output.