Understanding Diagnostic, Formative, and Summative Assessments

The way we assess students’ understanding of academic content has the potential to make a significant impact on their learning, how we see them, and how they see themselves. Accordingly, it’s helpful to have a deep understanding of the role each type of assessment plays. Today, we’re taking a look at the three primary forms of assessments—diagnostic, formative, and summative—with the goal of not only differentiating between them but also better understanding the purpose and potential power of each. 

At their core, each of the three primary assessment types serves a distinct purpose. Diagnostic assessments are used before instruction to help identify where students are in their comprehension of academic content. Formative assessments are used while content is being taught to understand what students are picking up, to guide their learning, and to help teachers determine what to focus on moving forward. Summative assessments are used after instruction to evaluate the outcomes of student learning: what, or how much, they ultimately learned. 

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. We’ll look at how and why this is the case, and we’ll also briefly highlight an assessment tool developed at Edmentum that helps educators implement diagnostic-driven learning paths and provides access to data-powered instructional tools focused on growth and proficiency. 

Diagnostic Assessments: Before Teaching 

When educators use carefully designed diagnostic assessments, they can better understand their students’ specific instructional needs. 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).” 

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. 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. 

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. 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. 

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. 

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.” Some examples include:

• Drawing a concept map in class to represent understanding of a topic
• Submitting one or two sentences identifying the main point of a lecture
• Turning in a research proposal for early feedback 

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. 

Exact Path: Powering 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. 

Moving Forward 

Assessments are a core part of teaching and learning. Their true value lies not only in measuring what students have learned but in informing how learning happens. Diagnostic, formative, and summative assessments each serve unique and essential roles in this process. When used together with thoughtfulness and care, they support more personalized and responsive instruction that helps students make meaningful progress. 

Whether educators are designing a quick classroom check-in or preparing a comprehensive final project, understanding the role of each assessment type can strengthen decision-making and planning. The result is more precise instruction, more targeted support, and more clarity for everyone involved. 

In the end, the goal is not just to assess learning but to support it at every stage. With a strong foundation in assessment literacy and access to the right tools, educators are better equipped to create learning environments that are truly reflective and growth-focused for every student. And that’s certainly a goal that’s well worth pursuing.