{
  "abstract": "Objective. We report the design and metric properties of the vocabulary test of the California Cognitive Assessment Battery (CCAB), which adaptively delivers 24 trials from a 600-word list ordered by difficulty, and describe the demographic variables associated with vocabulary test performance. Method. 2,181 English-speaking adults aged 18-89 completed 24 four-alternative synonym items administered as a 1-up/1-down staircase over 60 difficulty levels, with step sizes that started large (4 levels) and decreased after successive performance reversals. Two scores were compared: the QuickSIN estimate over all trials (the default) and the mean of the last four difficulty levels. Retests were available at 1 day in 100 participants and at 12 months in 307; reliability was assessed with Pearson and intraclass correlations. Twenty-one demographic correlates were screened in the 2,176 participants with questionnaire data, and a seven-term comprehensive regression model was compared with age-education-gender (AEG) adjustment, each with and without race indicators. A dichotomous Rasch model was fitted to the trial-level responses to calibrate the difficulty assignments of the stimulus set. Results. Median administration time was 227 s. QuickSIN and last-four scores agreed closely (r = 0.98) and retested at 0.83 and 0.82 at 1 day and 0.81 and 0.79 at 12 months. Education correlated r = 0.43 with the vocabulary score, weekly reading hours r = 0.39, age r = 0.29, highest household income r = 0.27, and parental education r = 0.26; English as a second language correlated r = -0.19; gender did not (r = 0.003). Vocabulary scores were 0.15 levels higher per year of age across the cross-sectional sample, with higher scores at older ages in every education stratum. The comprehensive model explained 32% of the variance (10-fold cross-validated R^2 = .31; AEG, 17% in the same participants) and attenuated but did not eliminate group differences: adjusted coefficients relative to non-Hispanic White participants were -0.27 SD for Hispanic, -0.38 for non-Hispanic Asian, -0.38 for non-Hispanic \"other\", and -0.76 for non-Hispanic Black participants, all significant. Word difficulties calibrated separately in each group agreed with the non-Hispanic White calibration at r = 0.96. Rasch calibration gave rho = 0.95 between assigned and estimated difficulty among the 316 well-sampled words, with a median displacement of 2 levels and a within-level spread of 2.9 levels; rescoring on the calibrated scale raised 12-month retest reliability to 0.84. Calibrated difficulty correlated rho = -0.85 with Brysbaert et al. (2019) word prevalence norms. Conclusions. The CCAB vocabulary test provides a reliable four-minute estimate of verbal ability that was higher at older ages in this cross-sectional sample. The assigned difficulty levels were broadly correct, but the spread of difficulty within a level limited the resolution of level-based scores to approximately 2-3 levels.",
  "abstract_shown": true,
  "affiliations": [
    "Neurobehavioral Systems, Inc., Berkeley, CA"
  ],
  "article_type": "PUBLISHAHEADOFPRINT",
  "arxiv": null,
  "author_total": 6,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "D. L. Woods"
    },
    {
      "name": "M. Blank"
    },
    {
      "name": "K. Hall"
    },
    {
      "name": "I. Jaramillo"
    },
    {
      "name": "K. Geraci"
    },
    {
      "name": "P. Pebler"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/exty9c72dv6sc.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.10.25.26366434",
  "fulltext_url": "https://www.medrxiv.org/content/10.64898/2026.10.25.26366434v1.full",
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  "language": null,
  "licence": "CC-BY-NC",
  "licence_label": "CC BY-NC",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "medrxiv",
      "neurology"
    ],
    [
      "openalex",
      "1803|Psychometric Methodologies and Testing"
    ]
  ],
  "openalex": "W7224112636",
  "pdf_url": "https://www.medrxiv.org/content/10.64898/2026.10.25.26366434v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-25",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/exty9c72dv6sc.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:57Z",
      "native_id": "10.64898/2026.10.25.26366434",
      "source": "medrxiv",
      "url": "https://www.medrxiv.org/content/10.64898/2026.10.25.26366434v1"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "medrxiv:neurology",
      "subfield": "neurology"
    }
  ],
  "title": "The Vocabulary Test of the California Cognitive Assessment Battery (CCAB)",
  "title_text": "The Vocabulary Test of the California Cognitive Assessment Battery (CCAB)",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:57Z",
  "url": "https://research.draconitic.com/paper/exty9c72dv6sc",
  "venue": "medRxiv",
  "versions": []
}