The Percentage of Vowel correct Scale in Persian Speaking Children

The Percentage of vowel correct (PVC) is one of the indices in the development of articulation and phonological skills in children that can be measured with speech samples that could be extracted from the single word or connected speech tests. The aim of this study is to introduce the PVC scale in Persian speaking children and investigate its validity and reliability. This validation study was conducted on 387 monolingual Persian speaking children aged between 3-6, that were selected from 12 nurseries and kindergartens in north-western of Tehran. The instrument for measuring PVC was Phonological Picture naming Test which its Content Validity Ratio (CVR) was assessed by Speech Language Pathologists and linguists. The comparison PVC scores in with and without phonological disorders (using Independent t-tests) and the relationship of PVC scores with age (using Kruskal Wallis test) was used for determining construct validity of the scale. Test-retest and scoring-rescoring were assessed, using Spearman’s correlation coefficients, intra-class correlation coefficients (ICCs), standard errors of measurement (SEMs) and coefficients of variations (CVs). Construct validity was confirmed with a significant difference between PVC scores of Children with and without phonological disorders (respectively: P<.001 and P<.05) and different age groups. Spearman’s correlation coefficients, intra-class correlation coefficients (ICCs), standard errors of measurement (SEMs) and coefficients of variations (CVs) for test– retest respectively were (.65,.65,.48,.08) and for scoring-rescoring respectively were (.71,.69,.33,.08). Results show that the PVC Scale is probably to be a reliable and valid instrument for evaluating articulation competence of Persian speaking children in clinical settings and research projects.