The score conversion process begins with a respondent’s LOA which is an absolute measure of their lexical ability on a logarithmic scale. The LOA is used to calculate vocabulary size for General English and the other sub-domains such as TOEIC, TOEFL, IELTS, etc. Each respondent's LOA is also cross referenced to a table of correlated standard test scores.
Naturally the table factors in the test makers' own published score conversions. LOA (not word count) is used to determine test scores because it insulates the results from changes that
naturally occur over time to both word difficulties and frequency counts in the sub-domains.
It is important to recognize that each test score that V-Check provides is based on the
AVERAGE SCORE attained by all respondents at the same LOA. In the chart above we see the respondent's LOA is 0.48 which corresponds to knowing 3,420 General English words and an average TOEFL score of 44. The full range of TOEFL scores reported at LOA 0.48 starts as low as 38 and goes as high as 52. Research indicates the primary variables causing higher and lower score variations at the same LOA are reading and listening speed. In other words, a person with the same vocabulary size who has a faster reading speed will score higher than a person with the same vocabulary size but a slower reading speed.
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V-Check
Test Score Conversion Methodology
Cihi, G. (Feb 2013 and 2018)
Soon after the launch of the V-Check test in 2008 many teachers and students beganasking
how vocabulary size correlated to standard English language proficiency test scoressuch TOEFL, TOEIC, IELTS, SAT and GRE. This paper describes how we process the score data
to establish the score conversions reported in WordEngine and V-Admin.
From the beginning we suspected that V-Check lexical ability scores would correlate strongly to standard English proficiency test scores however, the only way to demonstrate it
scientifically was to collect and process thousands of test scores from a variety of proficiency
tests. Over the years we collected 4,026 TOEFL scores;3,290 TOEIC scores, two hundred IELTS scores, and several dozen SAT and GRE scores. We have only recently started
collecting SAT and GRE scores. Approximately 80 percent of the test scores are self reported and 20 percent are actual scores sent by researchers using WordEngine. Taking the combined
7,500 test scores we produced scatter plots and correlation analysis. Results show reliable 0.81 correlation between respondent Lexxit of Ability (“LOA”) and test scores.
LOA General Words TOEIC TOEFL IELTS SAT/GRE
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We continue to monitor the relationship between LOA and standard test scores and update our score conversion graphs as the data warrants it.
For more information about how V-Check determines LOA please see these papers: "V-Check Lexical Diagnostic Assessment;"
