Diagnostic Learning Services: A Comprehensive Overview

The way we assess students’ understanding of academic content has a significant impact on their learning. Diagnostic, formative, and summative assessments each serve a distinct purpose, and understanding their roles is crucial for effective teaching and learning. When designed well and used with thoughtful intentionality, each of these assessment types can help drive student learning and give educators a clearer picture of what needs to be addressed, allowing them to better prepare for next steps.

Introduction to Diagnostic Assessments

Educational diagnostic testing is a form of assessment that occurs before instruction begins. Diagnostic assessments are used before instruction to help identify where students are in their comprehension of academic content. Sometimes referred to as pre-tests or pre-assessments, diagnostic assessments help determine students’ prior knowledge-what they already know-before they begin a course or unit of study.

Diagnostic assessment is a type of formative assessment (aka assessment for learning) designed to evaluate students’ prior knowledge, skills, and misconceptions before instruction begins.

Defining Diagnostic Assessments

As described by the IRIS Center at Vanderbilt, a diagnostic assessment “is a tool teachers can use to collect information about a student’s strengths and weaknesses in a skill area. These assessments can be formal (e.g., standardized achievement test) or informal (e.g., work samples).” Diagnostic tests are not graded.

Educational diagnostic testing can be used to evaluate students' level of academic achievement and learning potential and can sometimes lead to additional assessments if warranted by students' responses. Standardized tests and instructor-constructed assessments can be used as diagnostic tools to determine students' level of prior knowledge. One-on-one interviews may also be used as a diagnostic tool.

The Purpose of Diagnostic Assessments

The purpose of administering diagnostic tests is to try to determine what students already know about the concepts and skills to be covered by instruction. Diagnostic tests can determine if differentiated instruction is need, and discover students' preferred learning styles as well as their strengths, weaknesses, and misconceptions.

Once educators have this information, they can tailor the content of the unit or course accordingly, increasing the likelihood of effective learning. At the same time, diagnostic assessments can preview upcoming content in a way that gives students a sense of what to expect and why those skills are valuable to learn. This can help lower anxiety and increase buy-in by giving students a clear roadmap of what lies ahead.

Diagnostic testing can also help instructors plan their instruction and develop curriculum by helping to determine whether or not classroom instruction is closely aligned with federal and/or state high-stakes tests. Since these assessments are intended for diagnostic or predictive purposes, they are not graded (McTighe & O'Connor, 2005).

Benefits of Diagnostic Assessments

Tailored Instruction

When educators use carefully designed diagnostic assessments, they can better understand their students’ specific instructional needs. By beginning instruction with where students are, additional instruction time is gained which can be used to go over concepts the class has not mastered more slowly or cover more concepts than originally anticipated.

Metacognition Support

Sharing the results of diagnostic assessments with students can also support metacognition by helping students reflect on what they know and identify areas for improvement.

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Increased Motivation

When designed and framed well by educators, diagnostic assessments can even motivate students to strengthen the skills they already possess and invest effort into practicing those they are still working to develop.

Empowering Tool

Ultimately, diagnostic assessments can be empowering for both students and educators. They provide a clearer direction for instruction and support more individualized, targeted learning. When schools adopt diagnostic assessment strategies thoughtfully and consistently, they create a culture in which instruction begins with clarity and purpose.

Predicting Performance

Diagnostic tests are designed to closely follow what will be asked on a summative assessment. Diagnostic tests can also be used to predict how well students will perform on high-stakes tests used to meet No Child Left Behind guidelines and state standards. In this respect, they can be considered a combination of both summative and formative assessments.

Implementing Diagnostic Tests Efficiently

In order for diagnostic testing to work, instructors need to identify what competencies they want their students to have mastered. Based on that information, they must decide what tasks students should complete in order to determine each student's level of readiness regarding the competencies. Instructors can then go over their lesson plans and make any necessary adjustments. Some instructors may not plan their first lesson until they have seen the results of the diagnostic testing and can analyze exactly where students are with respect to prior knowledge.

Diagnostic pre-assessments can come from standardized assessments or be instructor developed. One possibility is to take the skills from summative assessments, which reflect what instructors think their students should know. This is accomplished by looking at specific skills and concepts the test is looking to assess and then developing the diagnostic test. This is also a good way of checking the effectiveness of instruction once the summative assessment has been given, because instructors can easily see what their students knew before instruction began and compare it with the post-intruction summative assessment results (Wormeli, 2006).

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Diagnostic tests should not be too large or complex and should only look to assess specific skills and concepts. For example, instructors could have their students solve three math problems that represent what will be taught. When creating diagnostic tests, instructors should consider the following:

What skills are to be assessed,
Whether the assessment allows students to demonstrate mastery of those skills,
If every component of the skills accounted for in the assessment,
If students can respond in a different way than expected and still show mastery of the concepts, and
If the assessment is a test of the process or the content (Wormeli, 2006).

Formal vs. Informal Diagnostic Testing

Diagnostic testing can be both formal and informal. Formal diagnostic testing includes standardized tests that can be used to assess particular skills, giving objective data on skill levels. However, the validity of such tests can be debated, and there is some concern about test bias. Additionally, standardized tests may assess more or fewer skills than those that will occur during instruction. The formal approach to diagnostic testing can be implemented within a classroom, a department, or within a school. It can also occur within a school district, state, or nation.

Informal diagnostic testing approaches can provide more flexibility, such as one-on-one questioning or small-group testing; but they still must follow the principles of diagnostic testing, meaning that they must assess only what is slated to be taught in the classroom and cover all concepts and skills (Highland Learning, n.d.).

Diagnostic Testing in the Classroom

Diagnostic testing must be aligned with predetermined learning objectives and should be built into the regular classroom routine. The assessments should be relatively short, valid, and free from bias. In order to accurately use diagnostic testing, instructors must be willing to modify course content and their teaching methods based on the information they receive from the assessments. This could mean covering subjects and concepts assumed to be already mastered, or not covering concepts that were originally planned if the skills and concepts have already been mastered. Instructors should also take care to assure that the assessment's directions are clear and cannot be misunderstood. Students should also be told why they are taking the diagnostic test and reminded that it is not going to be graded which helps alleviate any possible test anxiety or stress (Highland Learning, n.d.).

Diagnostic reports can show specific errors that students have made which can make it simpler to increase student performance and help schools, districts, and states meet their achievement goals. In fact, at least one publishing company has developed predictive assessments that are specifically aligned to each state's high-stakes tests (Starkman, 2006).

Diagnostic Testing for Preschool & Kindergarten

Diagnostic testing can also be used at the preschool level. As of 2002, 17 states had state-required diagnostic testing for kindergartners (NCEDL/Educations Week, 2001, as cited in "School Readiness and Assessment," 2002). This information can be used to place students in different classrooms based on ability so that those who need additional help can receive a more individualized education covering the foundational concepts on which all other competencies in future grades are based. These results should also be shared with parents so that they can help their children work on skills they need to master. These assessments can also be used to provide a baseline for future assessments.

An example of diagnostic testing in kindergarten might include an instructor asking students to draw a picture of body parts related to the different senses and requesting that they show what each part does. The instructor models the process by drawing an eye on the chalkboard and telling students the eye is used to see things. As students are working on their drawings, the instructor walks around the room to ask clarifying questions to help students articulate what they want to draw (such as seeing an ear and asking the child what an ear does). Based on what the instructor sees and learns about the students, the students may then be divided into groups for differentiated instruction. At the end of instruction, the instructor can have the students perform the same task of drawing the body parts and showing what each part does and compare the results with their original assessment to check student learning. Based on the new results, students may be moved to different groups (McTighe & O'Connor, 2005).

District & State Testing

If diagnostic testing is administered statewide or district wide, it can help assure consistency and standardization and gain information about the entire district or state. It can also help keep curriculum aligned with state standards and help assure student success on assessments used to meet No Child Left Behind Act standards. From a school's perspective, the data may affect the organization of a classroom, the number of aides in the room, and whether or not students receive more individualized attention. For instructors and students, diagnostic testing can improve teaching and learning and help keep students engaged since they will learn new material and not material they have already mastered (Highland Learning, n.d.).

Addressing Learning Gaps & Enabling Acceleration

Diagnostic testing may also reveal that there is a learning gap if it is assumed that students know concepts that were taught in previous classes. In an ideal situation, those students who have a large knowledge gap in what they should know and what they actually do know could be worked with separately or moved to another class before instruction actually begins. Diagnostic testing may also reveal that students know more than what was originally assumed, enabling the instructor to move forward at a faster pace and making it possible to cover more material than originally intended.

Diagnostic Assessment vs. Formative and Summative Assessments

It is important to differentiate diagnostic assessments from formative and summative assessments.

Formative Assessments: During Teaching

Formative assessments are used while instruction is in progress. They allow teachers to monitor students’ understanding of content and their ability to apply new skills. Because formative assessments provide ongoing feedback to both students and teachers, they are essential for adapting instruction and improving learning outcomes. As explained by the Eberly Center at Carnegie Mellon University, formative assessments are used to “help students identify their strengths and weaknesses and target areas that need work” and also to “help faculty recognize where students are struggling and address problems immediately.” The Eberly Center also notes that formative assessments “are generally low stakes, which means that they have low or no point value.”

When given regularly in a low-stakes format, formative assessments become a routine part of the classroom environment. This helps reduce stress for students and provides more authentic insight into their learning. The key benefit of formative assessments is that they are given during instruction, creating opportunities for educators to respond in real time. If a lesson isn’t effective, they can adjust. If students are performing really well, teachers can reinforce that success and continue building on it. In both cases, the instruction becomes more responsive, which ultimately benefits learning outcomes.

It’s worth noting that formative assessments also support students’ metacognition by helping them understand their strengths and identify specific areas for improvement. This allows learners to immediately implement feedback and make adjustments while still engaging with the content, rather than receiving feedback only after the course has moved on-when opportunities to apply that feedback are often limited or no longer available. This timely feedback cycle fosters a deeper, more active role for students in their own learning journeys.

Summative Assessments: After Teaching

At the conclusion of a course or unit, summative assessments are used to evaluate student learning. These assessments are typically higher stakes and may include final projects, essays, comprehensive tests, presentations, or performances. When thoughtfully designed, summative assessments can be highly beneficial for educators and students alike. The Teaching Commons at Stanford describes them as follows: “Effective summative assessments provide students a structured way to demonstrate that they have met a range of key learning objectives and to receive useful feedback on their overall learning. They should align with the course learning goals and build upon prior formative assessments. These assessments will address how well the student is able to synthesize and connect the elements of learning from the entirety of the course into a holistic understanding and provide an opportunity to provide rich summative feedback.”

Clear, detailed rubrics are often a key component of effective summative assessments. Rubrics clarify the criteria students are being assessed on and provide both students and teachers with a shared understanding of expectations. When students are given access to the rubric in advance, they can approach the assessment with greater intentionality and confidence.

Another valuable addition to summative assessments is student reflection. When students reflect on what and how they have learned, they strengthen their metacognitive abilities and make the assessment experience more meaningful. Reflection also helps shift the assessment toward what the University of Illinois Chicago’s Center for the Advancement of Teaching Excellence calls Assessment as Learning (AaL). According to their definition, AaL “provides student ownership of learning by utilizing evidence-based learning strategies, promoting self-regulation, and providing reflective learning.” This can work alongside Assessment of Learning (AoL), which focuses more on evaluating outcomes and student proficiency. Educators can design summative assessments that incorporate both approaches, resulting in assessments that not only measure student learning but also contribute to it. When this balance is achieved, summative assessments become more than a final grade-they become a valuable, reflective capstone to the learning process.

Key Differences

Although some consider diagnostic testing a type of formative assessment, it differs in that formative assessment should be ongoing in nature, occurs once instruction has begun, and checks students to ensure they are making adequate progress in learning the skills and concepts presented in class. Diagnostic testing is not ongoing and is completed before instruction begins. The similarity lies in the fact that both can-and should-be used to help guide instruction.

Using Diagnostic Tests with Formative & Summative Assessments

Recent research has shown that the regular use of both diagnostic testing and formative assessments benefits both instructors and students (Black, Harrison, Lee, Marshall & Wiliam, 2004, as cited in McTighe & O'Connor, 2005). Diagnostic testing can set the stage for instruction and where the instructor should begin with students, and ongoing formative assessment can assure that both the instructor and students are still on the right track for successful student outcomes. By finding the appropriate starting point for instruction and dividing students into proper skill levels, instructors can more effectively meet each student's learning needs and keep everyone engaged in the learning process. By using formative assessment to assure students are mastering the concepts and skills presented in class or to make adjustments to instruction, instructors can provide specific and timely information to students regarding what they still need to work on and guide their own methods of instruction for maximum effectiveness.

Tools for Diagnostic, Formative, and Summative Assessment

For K-12 educators building an assessment system that supports both student growth and proficiency, Exact Path and Standards Mastery work together to power a successful diagnostic, formative, and summative assessment strategy.

Exact Path’s diagnostic assessments are valid, reliable, and adaptive, pinpointing each student’s readiness level in math, reading, and language arts. These diagnostics integrate seamlessly with NWEA MAP Growth, Renaissance Star, and several state assessments to personalize learning without additional testing. Students are automatically placed on personalized learning paths based on these insights and have shown significant growth-up to 3x that of the average intervention-and those gains translate to improved performance on summative assessments like NWEA, Renaissance Star, and various state exams. Additionally, psychometric studies across 26 states confirm that Exact Path diagnostics predict state test performance, as well as SAT and ACT scores, making them a powerful driver of both instructional decision-making and summative success.

Standards Mastery provides formative assessment and state test preparation by offering pre-built standards-aligned checks year-round and independent practice that help educators monitor progress, close gaps in real time, and ensure readiness for high-stakes testing. Together, these tools form a cohesive system: identify needs diagnostically, respond with ongoing formative checks, and ultimately boost summative outcomes through targeted skill instruction and standards mastery.

To keep students motivated, Exact Path includes challenge badges and digital trophies that reward effort and progress. Educators and administrators also gain access to robust reporting that fuels data-driven instruction and systemwide improvement.

The Business of Diagnostic Testing

There are companies that parents can use that specialize in diagnostic testing. For a fee, they use national standardized assessments and assessments that are supposed to be aligned to state standards in order to determine grade equivalents, specific subject strengths and weaknesses, and the learning styles most appropriate for each student. With the passage of the No Child Left Behind Act, some companies advertise that their tests are aligned with benchmarks and standards to assess student mastery and adequate yearly progress (Felix & Finley, 2005). This type of marketing can be effective in selling a product to parents who are concerned that their children are not progressing well enough to pass high-stakes tests and are at risk of being retained or not receiving their high school diploma.

Even in the current high-stakes testing learning environment, some school districts are phasing out certain high-stakes tests and adopting a less stressful system of diagnostic testing. The Chicago school system, which serves over 430,000 students, decided that beginning with the 2005-2006 school year, schools would no longer use the Iowa Tests of Basic Skills and instead adopt reading assessments that were aligned to the state's standards used for meeting No Child Left Behind Act accountability requirements. They planned to administer the diagnostic tests three times a year and provide instructors with the assessment results within two weeks so that they could use the results to help guide their instruction and monitor student progress. The results are also shared with students' parents so that they can see if their children are making progress, what skills they have mastered, and what skills they still need to master. With the implementation of diagnostic testing in lieu of the Iowa Tests of Basic Skills, student promotion after grades three, six, and eight will depend on students' performance on the state test and other criteria (Bradley, 2005).

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