What is the Difference Between a Universal Screener and a Diagnostic Assessment Tool?

Source: ONlit (https://onlit.org/pd-silde-deck/next-steps-in-literacy-instruction-book-study/)

A screener is not a diagnosis but instead can help identify students that may need more support in learning to read before they fall behind and is administered with all students multiple times throughout the school year.  They are evidence-based, brief and standardized.  In this way, a screener is like having your temperature or blood pressure checked at the doctor’s office.  When these measurements are outside of the normal range, they indicate that further detailed assessment, intervention, and follow-up are needed.   The follow-up assessment is where a diagnostic assessment tool would come in.

A diagnostic assessment is akin to a blood test or diagnostic imaging, whereas a screener is like a body pressure or body temperature check.  After the blood pressure or temperature is checked to see if there is a problem, the blood test or diagnostic imaging would help identify where the problem lies (e.g., cholesterol levels, blood sugar levels). 

Similarly, a diagnostic assessment in literacy would provide more detailed information about the student’s skills.  For example, if a student is not meeting the benchmark for their grade level in the Phoneme Segmentation Fluency measure of Acadience Reading K-6, this may indicate that the student has trouble with segmenting words into sound segments and a diagnostic tool like ELPATS (Early Phonemic Awareness Tool Surrey) could provide further information about where the student struggles with phonemic awareness.  We could use ELPATs to see if a student struggles with hearing the first sound in words or last sound in words or whether they can segment words with two sounds but struggle with segmenting words with three sounds.

In many ways, a screener and a diagnostic tool can effectively be used together to not only identify students who may be at-risk for further reading problems but also, be used to inform instructional decisions and for planning purposes.  Progress monitoring tools are quick, formative assessments that can also be used to regularly assess student performance (e.g., every two weeks) to see if the student is making good progress and whether the intervention plan is working or if changes need to be made.  Acadience Reading K-6 have measures for progress monitoring.  See the graphic below:

(Source: ONlit )

Please see this video from the ONlit website featuring Dr. Stephanie Stoller, as she explains the difference between screeners and diagnostic assessments:

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