Parental report of vocabulary in 3- to 6-year-old Polish children: Reliable but not valid.

What is already known on the subject Parental checklists are commonly used to assess the vocabulary of children younger than 4 years of age. Previous research has indicated that parental checklists are reliable in terms of internal consistency and valid in terms of predictive and convergent validity. What this paper adds to the existing knowledge This study introduces a parental checklist designed for assessing the vocabulary of monolingual Polish-speaking children aged between 3 and 6 years. Statistical analyses reveal that while the parental checklist exhibits high reliability, and the scores on the checklist correlate with direct measures of vocabulary, the agreement between parental reports and direct vocabulary measures (i.e., validity) is notably low, particularly when examining individual test items. What are the clinical implications of this work? These findings underscore the importance of exercising caution when using parental vocabulary checklists with children aged between 3 and 6 years. These checklists can serve as a replacement for direct vocabulary tests only when the general/overall score is needed. However, when specific words are the subject of interest, parental reports may not be a valid measure.