The school counselor suggested that the special child must undergo the Peabody Picture Vocabulary test. Is this the most appropriate test to assess the child’s verbal intelligence? Find out.
A Background on the Test
The Peabody Picture Vocabulary Test or the PPVT was first launched in 1959 by two pioneers in the field of special education, Llyod M. Dunn and Leota M. Dunn. The PPVT became one of the most popular standardized tests to assess the verbal intelligence of an individual. It has been revised many times. The first revision was the PPVT-R, which came out in 1981, and it is simply an expanded form of the original Peabody Picture Vocabulary Test.
The next version, which came out in 1997, was the PPVT-III. In this version, the content has been updated and can be used for identifying the special needs of students. Then, Leota passed away in 2001 and Lloyd in 2006. Their son, Douglas M. Dunn, who was also involved in the creation of the PPVT versions, co-authored the latest one, the PPVT-IV. This is one of the speech and language assessments counselors recommend.
Purpose of the Test
The Peabody Picture Vocabulary Test is one of the most commonly used assessment tests that measure verbal ability in standard American English vocabulary. It measures the receptive processing of examinees from 2 to over 90 years old. And this measurement serves multiple purposes.
- If utilized on a school-age child, the PPVT can estimate the child’s scholastic aptitude. The test can reveal high or low verbal abilities, identifying possible learning disabilities.
- The PPVT may also be used to identify language disorders of children.
- For children who are emotionally withdrawn, suffering from mental retardation, or having speech or reading problems, the PPVT can be utilized to assess their verbal intelligence.
- The PPVT is also useful as a verbal ability test for people who have physical disabilities yet still retain functional visual and auditory capabilities.
Administration of the Test
The Peabody Picture Vocabulary Test is a relatively short test. It lasts about 20 to 30 minutes. To administer the PPVT, the examiner presents a series of pages that contains four black-and-white pictures. Each picture is numbered. Then, the examiner says a word and the examinee will identify the number of the picture that best corresponds to the word. If the examinee has speech problems, he or she may point to the picture.
Limitations of the Test
The administration of PPVT outs certain limits on the test. It cannot be used on people who suffer from blindness and/or deafness. Psychologists may also need to consider other types of verbal ability assessments when measuring the intelligence of adults who have severe to profound mental retardation because a considerable number of the pictures include images of children.
Each version of the PPVT has been nationally standardized using examinees from various age groups, from children to adults. Thus, the raw scores are equated to mental age, using the norms obtained from standardization. But the scores can also be converted to percentile rank or to a standard deviation IQ score.
The concurrent validity of PPVT has been established using comparisons with other vocabulary tests. For example, the correlation of PPVT scores with that of the Stanford-Binet Vocabulary Subtest ranges between 0.68 and 0.76. The reliability of the PPVT was measured in two ways, the split-half and the test-retest. For the former, the reliability ranges from 0.60 to 0.80. For the latter, the range is from 0.70 to 0.90.
The only caveat is that the population used to establish the norm did not include examinees that suffered from a physical handicap.