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Diagnostic Assessment as a Tool for Identifying Learner Needs

November 12th, 2020

Diagnostic assessment plays an important role in how teachers identify and understand learning needs. It’s important to understand that diagnostic assessment is not the same as diagnosis. By understanding the difference between these two terms and how each might play a role in school-based supports for students, teachers will be in a strong position to support all students’ learning needs.

Process and Product

The best way to differentiate diagnostic assessment from diagnosis is to understand that one is a process and the other is a product.

  • Diagnostic Assessment = process of identifying the reason for a problem
  • Diagnosis = product of a comprehensive evaluation to match a student’s presenting symptoms with the criteria for a specific disorder

Both of these terms have roles to play in identifying student learning challenges and needs, but they serve very different purposes.

What is Diagnostic Assessment?

Diagnostic assessment is the process of using multiple measures and reports to identify student strengths and needs in specific skill-areas so that teachers can provide instruction to address learning needs. Diagnostic assessment directly guides academic, curricular, and instructional decisions because there is a better understanding of what a student does or does not know in relation to specific learning goals.

The types of assessments often used for the diagnostic assessment process include universal screening, classroom observations, progress monitoring, and qualitative data that are specific to the learning gap. Diagnostic assessment also involves instruction in order to see how a student responds to efforts to close learning gaps. As compared to more general assessments, diagnostic assessment seeks to identify the specific skills that a student needs to learn by isolating specific learning gaps.

Types of assessment often used in the diagnostic assessment process

For example, universal screening assessment results might show that a student has weak decoding skills, but not which letter sounds the student needs to learn. Additional diagnostic assessment can be used to gather more detailed information. In this example, the teacher might have the student complete a letter sounds inventory along with a sight word measure. These diagnostic data pinpoint what specific skills the student needs to learn. With that information, the teacher can provide instruction on those specific skills.

Diagnostic Assessment and Progress Monitoring

In order to measure student improvement, a progress measure that matches the instructional focus should be used at regular intervals. In the case of decoding instruction, weekly pseudoword decoding assessments would make sense. When student progress data indicate improvement, then further assessment is not needed. If the progress data shows that the student is not making gains, then additional careful review of the intervention procedures and integrity as well as consideration of other options is needed. In some cases, additional diagnostic assessment might be used to learn more about the specific learning gaps.

For many students, a process of diagnostic assessment and targeted instruction and intervention will result in learning improvements. For some students, the diagnostic assessment process and subsequent intervention with progress monitoring might not yield the gains needed. When a student does not make gains despite evidence-based instruction, implemented with integrity, it might be the case that the student meets the criteria for a learning disability and may qualify for special education services. (Importantly, eligibility for special education does not require a diagnosis of a specific disability. In some cases, a formal diagnosis might be made as part of a comprehensive evaluation, but not always).

How Diagnosis is Different

As noted, diagnosis is the product of a set of procedures related to determining if a student demonstrates the characteristics, or symptoms, of a specific disorder. To determine if a diagnosis is present, a number evaluation activities are conducted, including a a comprehensive evaluation to determine if the student qualifies; the presence of a diagnosis does not automatically mean that a student is eligible for special education. Instead, a team made up of the student’s teacher, parents, specialists, a psychologist, and sometimes others must determine what evaluation data to request and then meet to consider whether the accumulated data indicate the need for special education services.

Many comprehensive evaluations are conducted by school-based specialists while others are completed by contracted specialists including clinical psychologists and physicians. The types of professionals who participate in comprehensive evaluation activities depend on the reason that the student was referred for evaluation. For students with already diagnosed medical conditions such an orthopedic impairment, deafness, blindness, or Down syndrome, prior medical diagnosis can be used as part of the comprehensive evaluation.

For some referrals, the team will also need to gather recent data about the student’s school performance as well as conduct additional testing. The team must review the accumulated data to determine if the student demonstrates persistent underachievement and will benefit from specialized instruction.

Sometimes, a student who has been diagnosed with a certain disorder might not qualify for special education because overall achievement is strong. Nonetheless, the student’s symptoms require some type of accommodations or supports to succeed in schools. Examples include students in wheelchairs who need ramps to navigate buildings or students who are hard of hearing who require priority seating and assistive hearing devices. The actual instruction does not need to be changed, but school staff do need to accommodate the student’s specific needs. In these cases, the student might qualify for what is known as a 504 plan. This type of plan is based on the Americans with Disabilities Act and a rule from section 504 of a law related to supporting individuals with disabilities. All public schools are required to have procedures to develop and implement 504 plans just as they are special education programs.


Although both diagnostic assessment and diagnosis can play important roles in supporting student success, these terms have very different meanings and uses in schools. Diagnostic assessment is a process whereby teachers identify and address student learning needs using a sequence of assessment and instruction. Diagnosis is the product of evaluation procedures, but is not required for special education services.  Formal diagnoses are more common in cases of medical conditions but are sometimes used when a learning disability or behavior disorder is present.  For students whose diagnosis and current needs do not warrant special education services, a 504 plan might be used to ensure accommodations so the student can access learning opportunities.


Illuminate Education equips educators to take a data-driven approach to serving the whole child. Our solution combines comprehensive assessment, MTSS management and collaboration, and real-time dashboard tools, and puts them in the hands of educators. As a result, educators can monitor learning and growth, identify academic and social-emotional behavioral needs, and align targeted supports in order to accelerate learning for each student. 

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