I am seeing a lot of 3- and 4-year-olds who fail the PLS™-5 Screening Test, then score 78–85 when they take the full PLS™-5. Any insights you can provide about these test results?
A criterion-cut score is selected on a screening test to best differentiate a group of typically developing children from a group of children with a disorder. These two groups overlap in performance somewhat—they are not completely distinct groups. Low-performing typical kids and higher performing atypical kids with a mild language disorder may perform similarly.
Because of the overlap in the distribution of scores of both groups of children, a criterion score may be chosen that slightly over-identifies children who do not have a disorder as needing more testing or under-identifies children with a mild disorder who are not flagged for additional testing. Many screening tests are designed with a cut score that slightly over-identifies children who need additional testing so that clinicians don’t miss children who have a disorder.
The example the clinician provides (children scoring 78–85 on PLS-5) indicates that the PLS-5 Screener is not screening out children with a mild disorder (standard scores of 78 to 85 translate to a percentile rank of 7 to 16—not a score in the average range, but not low enough to qualify a child for services in many programs.) It would be a concern if the clinician found that many children failed the Screener, but had PLS-5 scores of 86+, well into the average range of the test. But this clinician has a population of children who are having some degree of language issues—84–93% of same age peers score better than they do. The PLS-5 Screener isn’t identifying children for direct services, but is identifying children with low language skills that should be monitored. Since the children she is testing may not qualify for direct services, she may consider other ways to foster improved language skills for these children scoring somewhat low such as team teaching in the classroom for certain lessons, providing the teacher with techniques to facilitate improved vocabulary or syntactic skills, etc.