Generic Test Analysis Template



Test Review: Expressive Vocabulary Test (EVT)

|Name of Test: Expressive Vocabulary Test |

|Author(s): Kathleen T. Williams |

|Publisher/Year (Please provide original copyright as well as dates of revisions): AGS 1997 |

|Forms: no alternate forms |

|Age Range: 2 ½ through 90 years |

|Norming Sample: The EVT was co-normed with PPVT-III in 1997 using a stratified sample reflecting US census data. The norming process took four years in stages: 1. content specification, 2. two |

|pilots to address assessment approach and develop item pool, 3. national try-out for scoring rules, item analysis, and detecting bias and, 4. standardization. |

|Total Number: 2 725 in standardization sample (The national tryout included 908 people ranging in age from 2 years, 6 months to 21 years, with slightly more females.) |

|Number and Age: 2 years, 6 months to 90+ years of age |

|Location: 4 regions, 240 sites |

|Demographics: Extensive details of characteristics are provided by gender, geographic region, race/ethnicity, and SES (and also by combined variables). Tables are provided (Williams, 1997, pp. |

|54-60). |

|Rural/Urban: No information |

|SES: Caregiver or parent educational level was chosen as proxy for SES. There was slight under-representation in the Grade 11 or less category and overrepresentation in the 4 or more years of |

|college category. |

|Other (Please Specify): The author also considered combined variables in order to more closely match population distribution. For example: parent’s education/race/region for low SES Hispanic |

|males living in the South sample corresponds with population statistics for that region. |

|Summary Prepared By (Name and Date): Eleanor Stewart 20 April 2007 |

|Test Description/Overview |

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|Purpose of Test: This test assesses expressive vocabulary and word retrieval. Though specifically designed as an expressive vocabulary and, when used in conjunction with the PPVT-III as a word |

|retrieval assessment tool, the EVT authors also state that the test “can be used in several ways in clinical and school settings” (Williams, 1997, p. 2). They offer that the EVT can be used for|

|preschool screening, understanding reading difficulties, and in monitoring growth from preschool through school years to adulthood. They also state that the test can be used in research and in |

|assessing second language learners. |

|Areas Tested: |

|Oral Language Vocabulary Grammar Narratives Other (Please Specify) |

|Other: word retrieval |

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|Who can Administer: The manual indicates that a wide range of service providers could be expected to be familiar with this test’s specific administration. Such individuals include: |

|paraprofessionals working under supervision of qualified professionals, educators, psychologists, reading specialists, and speech-language pathologists. However, regardless of who administers |

|the EVT, test interpretation is the responsibility of qualified professionals with graduate level training in assessment. |

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|Administration Time: The test should take approximately 10 to 25 minutes. Table 1.1 provides average administration times for 21 age groups in the norm sample, which is a useful guideline to be |

|used in conjunction with other examinee characteristics such as ability, temperament, and mood. |

|Test Administration: Teaching and prompting procedures are described in detail in the manual and test administrators are expected to follow these procedures. Basal and ceiling rules are stated |

|(i.e., 5 consecutive correct/incorrect items). Two examples are provided to demonstrate how to label. Similarly, two examples are provided to demonstrate how to respond to synonyms items. A set |

|of carrier phrases can be used to elicit synonyms. For example, the examiner may offer, “Tell me another way to say…”, or “What else can you call a…” (Williams, 1997, pp. 12-13). The authors |

|note that the examiner can use the sample phrases “or another that you find to be more appropriate for the age and functioning level of the examinee you are testing” (p. 13). Pacing the |

|presentation of items and the response interval are discussed with the view that at a 10 second interval should be sufficient for responding. If the examinee does not respond in that time frame,|

|the examiner is encouraged to move on so that the examinee does not become discouraged. The authors also provide sample phrases for the examiner to use such as: “Let’s go on”, “Listen |

|carefully”, “I missed your answer. Say it again” and “That is a good answer” (p. 13). Teaching the examinee how to respond is outlined in the manual with directions. Teaching items are |

|identified on the record form with an icon letter “T”. Specific prompting rules are given that apply to all EVT items. For example, Prompting Rule #2 states: “Prompt if the examinee responds |

|with a form of the correct response by saying: Yes, but give me a different form of that word. For example, use this prompt if the examinee responds with starting instead of start for Item 65, |

|begin” (p. 14). Synonym items require specific prompts which are also described in the manual. |

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|Comment: Because the prompting rules and the teaching outline are only in the manual, I think that the examiner must be very familiar with these procedures before administering the test. There |

|is no time to be checking the manual once the student is ready to participate in testing. |

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|Scoring guidelines and calculation of the raw score are described in the manual. Examples illustrated with completed record forms are provided. |

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|The final section in the chapter on administration provides a useful list of additional correct responses. Also listed are further examples of incorrect responses drawn from the standardization |

|sample (Williams, 1997, pp. 21-32). |

|Test Interpretation: The manual provides detailed information on interpretation in relation to normative statistics. Drawing on the strength of having normed both the PPVT-III and EVT on the |

|same population, direct comparisons in scores can be made that will assist in determining the nature of the examinee’s vocabulary difficulties. A score comparison method is offered that consists|

|of calculating the difference in EVT and PPVT-III standard scores. The difference is then expressed as a) statistically significant (see Table B.4) at .15, .10, .05, and .01 or b) a percentage |

|of the sample with this difference (Table B.5 or B.6, e.g., >25% to 1%). |

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|EVT includes a word retrieval component. The author outlines the possibilities for interpretation when there are: a) no differences in scores and b) differences in scores. An example was given |

|of a student with dysnomia where further testing with OWLS was suggested. Guides in selecting additional diagnostic testing are provided. |

|Standardization: Age equivalent scores Grade equivalent scores Percentiles Standard scores Stanines |

|Other: Confidence intervals at 68, 90, and 95%. |

|The test was standardized on English speakers. The author states that caution should be used when assessing individuals for whom English is a second language and that, in such situations, |

|results should be used a baseline measure of vocabulary only. Examinees who have visual or hearing impairments or who have significant physical limitations may be presented with modifications. |

|Reliability: |

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|Internal consistency of items: There was a high degree of uniformity. Alpha and split-half reliabilities reported for 25 age groups range from .83 - .97 with a median of .91. |

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|Test-retest: Stability was evidenced. The test was administered twice to 226 randomly selected subjects in four age groups. Corrected coefficients were reported in the range .77 to .90. |

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|Inter-rater: not reported |

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|Other: There was a SEM median of 4.6 across 25 age ranges computed from split-half reliabilities. |

|The Buros reviewer states, “Although the greatest change (or growth) in language abilities is expected at the youngest age levels, possible reasons for the rather low reliability for the |

|youngest groups are not discussed in the manual” (Bassai & Wasyliw, 2001, p. 477). |

|Validity |

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|Content: Extensive description of item development is provided. Items were selected from studies of high frequency and common usage vocabulary reflecting common life experiences in the U.S. |

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|Criterion Prediction Validity: Scores on EVT were compared to language and cognitive measures: OWLS (OC, LE and Oral Composite), WISC-III, KAIT, and K-BIT. |

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|Construct Identification Validity: The constructs to be tested (expressive vocabulary and word retrieval) are well defined. Table 5.4 reports means and SD of raw scores for the standardization |

|sample by age. The author states that data support that EVT demonstrates age differentiation with increases in mean raw scores that are consistent with what we know about vocabulary development |

|across lifespan (i.e., greater increases in early years, more gradual increases in middle years, tapering off after 50 years). Regarding word retrieval, the comparisons with PPVT-III show high |

|correlations, 60% shared variance, and provide evidence that word retrieval is indeed being measured. |

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|Differential Item Functioning: The author states that data support that EVT demonstrates age differentiation with increases in mean raw scores that are consistent with what we know about |

|vocabulary development across lifespan. |

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|Other (Please Specify): In order to establish the clinical validity, the EVT and PPVT-III (both forms) were administered to eight different clinical groups using matched samples with a |

|standardization group. Gender, race, SES, and region were considered. Groups included: speech impairment (N=50, no significant difference), language delay (N=39, significant difference), |

|language impairment (N=53, significant), mental retardation (N=44, significant), learning disability-reading (N=60, significant), hearing impairment (N=28, significant), and gifted (N=43, |

|significant). T-tests for paired samples were reported. |

|Summary/Conclusions/Observations: Throughout the manual, the author provides definitions of terms used so that even a naïve reader unfamiliar with statistical terms and test interpretation is |

|provided with sufficient guidance to accurately and fairly use the EVT in assessment. This test has impressive data to support its use in measuring expressive vocabulary. |

|Clinical/Diagnostic Usefulness: Given its extensive standardization, the authors are confident that EVT will provide an accurate measure of expressive vocabulary skills, and, if administered |

|along with PPVT-III, will assist in determining the nature of vocabulary difficulties. Although this test has strong psychometric properties, it is less used in clinical settings because of its |

|single focus on vocabulary. Clinicians tend to use global language tests at least initially. However, when poor vocabulary skills or retrieval difficulties are suspected, the EVT would be a |

|strong diagnostic measure to employ. |

References

Bassai, F., & Wasyliw, O. E. (2001). Review of the Expressive Vocabulary Test. In B. S. Plake & J. C. Impara (Eds.), The fourteenth mental measurements yearbook (pp. 475-478). Lincoln, NE: Buros Institute of Mental Measurements.

Williams, K. T. (1997). Expressive vocabulary test. Bloomington, MN: Pearson Education, Inc.

To cite this document:

Hayward, D. V., Stewart, G. E., Phillips, L. M., Norris, S. P., & Lovell, M. A. (2008). Test review: Expressive Vocabulary Test (EVT). Language, Phonological Awareness, and Reading Test Directory (pp. 1-5). Edmonton, AB: Canadian Centre for Research on Literacy. Retrieved [insert date] from .

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