Independent confirmation that vocabulary in use unfolds across levels of performance as expected can contribute to a more complete understanding of validity in standardized English language tests. This study examined the relationship between Lexical Frequency Profiling (LFP) measures and rater judgements of test-takers' overall levels of performance in the Speaking and Writing modules of the CELPIP-General test. In particular, the potential of measures such as lexical stretch and number of frequency bands accessed was examined. Randomized quota sampling from previously rated test-taker responses resulted in 200 speaking samples and 200 writing samples being compiled to create corpora of 211,602 running words and 70,745 running words respectively. Pearson r was used to examine the relationships between the LFP measures and rater judgements of CELPIP levels. Results point to significant correlations, with increasing CELPIP levels of performance generally accompanied by test-takers' increasing ability to produce greater numbers of words, deploy a greater variety of words, rely less on high-frequency vocabulary, tap into mid-frequency vocabulary, and access a greater number of frequency bands. These results underline the contribution of independently obtained lexical measures toward a fuller understanding of concurrent validity in standardized English language proficiency testing.