Quality of measurement in core lexicon (Kim et al., 2022)

Purpose: Core lexicon measures have received growing attention in research. They are intended to provide clinicians with a clinician-friendly means to quantify word retrieval ability in discourse based on normal expectations of discourse production for specific discourse elicitation tasks. To date, different criteria have been used to develop core lexicon measures by groups of researchers. The need for statistical guidance in pursuit of the psychologically robust measure has been recognized.
Aims: This study was to investigate the best criterion for accurate measurement. Specifically, we focused on two criteria (frequency vs. percentage) that have previously been used for the development of core lexicon measures.
Method: Core lexicon measures consisting of five different checklists by word class (verbs, nouns, adjectives, adverbs, and function words) and developed by the two criteria were applied to language samples produced by 470 cognitively healthy adults. Performance in word retrieval ability at the discourse level was modeled as a latent variable based on the observed proportions of the production of core lexicon items in two different sets of core lexicon measures using structural equation modeling.
Results: Results indicated that both criterion for core lexicon measures capture word retrieval ability in discourse. Greater residual variances were found in the core lexicon measure established by the percentage criterion compared to the one established by the frequency criterion. This indicates that the measure based on the percentage criterion is more affected by measurement errors.
Conclusions: The findings provide evidence that the frequency criterion is better to use for the development of core lexicon measures for core nouns, verbs, adjectives, and adverbs, but not for function words. However, our findings are limited to core lexicon measures based on language samples elicited by wordless picture books. This may not be easily applied to other core lexicon measures that use different discourse elicitation tasks due to the difference in quality and quantity of language samples. Ideally, the same approach should be replicated to evaluate the appropriateness of respective criteria in the development of core lexicon measures.

Supplemental Material S1. Core Lexicon checklists for Good Dog, Carl and Picnic developed by frequency and percentage criteria.

Supplemental Material S2. Mean number of different words/words produced by age and story (Good Dog, Carl [GDC], Picnic).

Kim, H., Schoemann, A. M., & Wright, H. H. (2022). Quality of measurement in core lexicon measures. Journal of Speech, Language, and Hearing Research. Advance online publication. https://doi.org/10.1044/2022_JSLHR-20-00722

目的：核心词汇量的衡量标准在研究领域受到了越来越多的关注。它们旨在为临床医生提供一种易于操作的量化手段，以衡量基于特定话语诱发性任务中话语生产的正常预期，对话语中词汇检索能力进行量化。迄今为止，不同的标准已经被各个研究团队用于开发核心词汇量的衡量标准。在追求心理上稳健的衡量标准的过程中，统计指导的必要性已被认识。目标：本研究旨在探究准确测量的最佳标准。具体而言，我们聚焦于两种先前用于开发核心词汇量衡量标准的标准（频率与百分比）。方法：基于两种标准（频率与百分比）开发的包含五个不同清单的核心词汇量衡量标准，针对470名认知健康的成年人产生的话语样本进行了应用。话语层面的词汇检索能力表现被建模为基于两个不同核心词汇量衡量标准中核心词汇项生产的观察比例的潜在变量，使用结构方程模型进行建模。结果：结果表明，两种核心词汇量衡量标准均能捕捉到话语中的词汇检索能力。与基于频率标准建立的核心词汇量衡量标准相比，基于百分比标准建立的核心词汇量衡量标准中存在更大的残差方差。这表明基于百分比标准的衡量标准更容易受到测量误差的影响。结论：研究结果提供了证据，表明频率标准对于开发核心名词、动词、形容词和副词的核心词汇量衡量标准更为适用，但不适用于功能词。然而，我们的发现仅限于基于无言图画书诱发性语言样本的核心词汇量衡量标准。这可能不易应用于使用不同话语诱发性任务的其他核心词汇量衡量标准，因为语言样本的质量和数量存在差异。理想情况下，应采用相同的方法来评估相应标准在开发核心词汇量衡量标准中的适用性。补充材料S1：基于频率和百分比标准开发的核心词汇量清单，用于《好狗卡尔》和《野餐》。补充材料S2：不同年龄段和故事（好狗卡尔[GDC]、野餐）中产生的不同单词/单词数量的平均值。Kim, H., Schoemann, A. M., & Wright, H. H. (2022). 核心词汇量衡量标准的测量质量. 语音、语言和听力研究杂志. 提前在线发表. https://doi.org/10.1044/2022_JSLHR-20-00722