Peabody Picture Vocabulary Test - Revised (PPVT-R)

The Peabody Picture Vocabulary Test, revised edition (PPVT-R) "measures an individual's receptive (hearing) vocabulary for Standard American English and provides, at the same time, a quick estimate of verbal ability or scholastic aptitude" (Dunn and Dunn, 1981). The PPVT was designed for use with individuals aged 2½ to 40 years. The English language version of the PPVT-R consists of 175 vocabulary items of generally increasing difficulty. The child listens to a word uttered by the interviewer and then selects one of four pictures that best describes the word's meaning. The PPVT-R has been administered, with some exceptions, to NLSY79 children between the ages of 3-18 years of age until 1994, when children 15 and older moved into the Young Adult survey. In the current survey round, the PPVT was administered to children aged 4-5 and 10-11 years of age, as well as to some children with no previous valid PPVT score.

Description of the PPVT

The PPVT-R consists of 175 stimulus words and 175 corresponding image plates. Each image plate contains 4 black-and-white drawings, one of which best represents the meaning of the corresponding stimulus word. There are also 5 training words and image plates. Readers who wish to examine more than a single example of the actual images (or "plates") presented to the child, should access the PPVT-R Manual and materials (Dunn and Dunn, 1981) or contact NLS User Services. There are two parallel forms of the PPVT-R; Form "L" has been used by the NLSY79 Child at all assessment rounds. PPVT items are numbered in order of increasing difficulty.

In 1986, the PPVT assessment was administered only in English. A Spanish version of the PPVT-R, the Test de Vocabulario en Imagenes Peabody or "TVIP," was introduced into the child survey in 1988 and used through the 2000 survey round for a small number of children who preferred to answer the Spanish version.  For this reason, post-1986 assessment results may be less culturally biased than the 1986 version. After 2000, the Spanish version of the PPVT was no longer administered.

Administration of the PPVT

Prior to 2000, the child viewed the images on the PPVT easel. Starting in 2000 the interviewer read from a laminated PPVT word list while the child matched the word by selecting one of four on-screen images designed to reproduce the pictures from the original PPVT easel.

Five training items are administered at the beginning of the PPVT assessment in order to familiarize children with the task. The first item, or starting point, is determined based on the child's PPVT age. Starting at an age-specific level of difficulty is intended to reduce the number of items that are too easy or too difficult, in order to minimize boredom or frustration. The suggested starting points for each age can be found in the PPVT manual (Dunn and Dunn, 1981).  

Testing begins with the starting point and proceeds forward until the child makes an incorrect response. If the child has made 8 or more correct responses before the first error, a "basal" is established. The basal is defined as the last item in the highest series of 8 consecutive correct answers. Once the basal is established, testing proceeds forwards, until the child makes six errors in eight consecutive items. If, however, the child gives an incorrect response before 8 consecutive correct answers have been made, testing proceeds backwards, beginning at the item just before the starting point, until 8 consecutive correct responses have been made. If a child does not make eight consecutive responses even after administering all of the items, he or she is given a basal of one.  If a child has more than one series of 8 consecutive correct answers, the highest basal is used to compute the raw score. 

A "ceiling" is established when a child incorrectly identifies six of eight consecutive items. The ceiling is defined as the last item in the lowest series of eight consecutive items with six incorrect responses. If more than one ceiling is identified, the lowest ceiling is used to compute the raw score. The assessment is complete once both a basal and a ceiling have been established.  The ceiling is set to 175 if the child never makes six errors in eight consecutive items.

Scoring the PPVT

A child's raw score is the number of correct answers below the ceiling. Note that all answers below the highest basal are counted as correct, even if the child answered some of these items incorrectly. The raw score can be calculated by subtracting the number of errors between the highest basal and lowest ceiling from the item number of the lowest ceiling.

As with PIAT Math and Reading Comprehension, it was possible, primarily in the pre-CAPI years, to improve the overall quality and completion level by utilizing information on the actual responses where "correct-wrong" check items had inadvertently been skipped by the interviewer. For a precise statement of the scoring protocol and the norm derivations, the user should consult the PPVT-R Manual (Dunn and Dunn, 1981, pp. 96-110, 126).

Age Eligibility for the PPVT

Variations in the patterns of administration are somewhat complex for this assessment so the user is encouraged to examine Table 4 in the Child Assessments--Introduction section in order to understand which samples of children took this test over the various survey years. 

Users are reminded that the eligibility of children for the PIAT and PPVT-R assessments is based on their "PPVT age," which can differ from their calendar age (in months). In creating the PPVT age in months, a child's age is rounded up to the next month if he or she is more than 15 days through a given attained month as of the survey date. When working with the PPVT-R or PIAT assessments, the "PPVT age" variable (PPVTMOyyyy) should be used.

In 1986, all children age three and over were given this assessment. In 1988, all ten- and eleven-year-olds (our "index" population) as well as other children age three and over who had not previously completed the assessment in 1986 were given this assessment. In 1990, all children age ten and eleven as well as all other children age four and over who had not previously completed the assessment were eligible for the PPVT-R assessment.  In the 1992 survey round, all children age three and over were eligible to be assessed. Thus, there are at least two survey points (1986 and 1992) in which all age-eligible children who were still being interviewed had a PPVT-R score. Of course, many of these children may also have had an intervening (at age 10 or 11) PPVT-R score. Starting in 1998, the administration of the PPVT-R was largely limited to 4- and 5-year-old children who had not been previously administered the test as well as the index group of children 10-11 years old. In 2004, 2006, 2010 and 2012, a small number of children outside of the age range for PPVT assessment but who did not have prior valid scores were administered the PPVT.

Norms for the PPVT

The PPVT-R was standardized on a nationally representative sample of children and youth. The norming sample included 4,200 children in 1979, and norms development took place in 1980 (Dunn and Dunn, 1981). For a comprehensive discussion of this norming procedure, researchers should refer to the PPVT-R Manual for Forms L and M (Dunn and Dunn, 1981). Age-specific standard scores (with a mean of 100 and standard deviation of 15) and corresponding percentile ranks are provided in the PPVT-R Manual.

Beginning in 1990, the procedure used to create the NLSY79 Child PPVT-R normed scores was refined in two important ways. First, children with raw scores that translated into standard scores between 20 and 39 are now normed using the PPVT-R Supplementary Norms Tables (American Guidance Service, 1981).  Second, raw scores that would translate to normed standard scores above the maximum provided are assigned standard scores of 160, and raw scores translating to standard scores below the minimum are now assigned standard scores of 20. Prior to 1990, children with these scores were assigned a standard score of zero.  The revised 1986-1988 normed scores are available in the current public data release.

Users may note one important distinction between the PPVT-R and PIAT scores--a difference of particular interest to those who plan to use both assessments concurrently. Whereas the PIAT assessments show relatively high mean scores (see discussions of the PIAT in the PIAT Math and Reading sections of this users guide), the PPVT-R mean scores are more comparable to those of the norming sample.

Completion rates for the PPVT

Table 6 in the Child Assessments--Introduction section contains the completion rate for the PPVT in the current survey round.

Validity and Reliability of the PPVT

The PPVT-R is among the best-established indicators of verbal intelligence and scholastic aptitude across childhood. It is among the most frequently cited tests in Mitchell's (1983) "Tests in Print." Numerous studies have replicated the reliability estimates from the PPVT standardization sample. The NLSY Child Handbook: 1986-1990 synthesizes much of this work. This report also provides cross-year (1986-1990) reliability and validity evaluation using the NLSY79 Child data.  The NLSY Children, 1992: Description and Evaluation contains an evaluation of the quality issues for the 1992 PPVT-R sample, which included the full spectrum of children age three and over. These analyses show strong associations between a full range of social and demographic priors and 1992 PPVT-R scores. The report also documents strong independent linkages between PPVT-R scores in 1986 and PPVT, PIAT Reading and Mathematics, and SPPC scores in 1992. Typically, stronger associations are found for white and Hispanic than for black children. Both of these documents are available on the Research/Technical Reports page.

Age and Racial Differences on the PPVT

The youngest children administered this test historically scored the poorest, probably reflecting their unfamiliarity with a testing environment. Their lower scores did not reflect lower status as these younger children have parents with more education than do the older children.

More than for any of the other assessments, substantial racial and ethnic variations exist for the PPVT, and these variations remain in multivariate analyses even with demographic and socio-economic controls. The reader is referred to The NLSY Children, 1992: Description and Evaluation for a more comprehensive evaluation of racial, ethnic, and socio-economic differentials in PPVT-R scores using the 1992 NLSY79 data which included PPVT-R assessment scores for all children age 3 years and over. This document is available on the Research/Technical Reports page.

PPVT Scores in the Database

Three types of PPVT scores are provided for each child:  a raw score, a standard score, and a percentile score. Documentation of the PPVT scores for the current survey can be found in Table 1 in the Child Assessments--Introduction section.