The Value of Interim Assessments

Helping students reach their full potential often starts with identifying each student’s academic strengths and areas of growth. But without frequently measuring progress across academic areas, educators are too often forced to be reactive once challenges have intensified instead of proactively offering support at the first sign of difficulty. 

That’s why interim assessments, which measure progress throughout the school year rather than strictly at the beginning or end, have grown in popularity. Several states are now implementing interim assessments as part of their assessment roadmaps. For independent schools, which have the flexibility to create highly targeted assessment programs that consider the whole child, interim assessments can be particularly valuable. 

Interim assessments give educators and school leaders the touchpoints they need to assess individual, class, and grade-level performance, allowing them to adapt curricula and offer additional support throughout the school year. When used correctly, interim assessments don’t necessarily lead to over-testing; rather, these brief tests can help keep students and educators on track and, in fact, reduce the stress associated with other assessments.

Here’s what K-12 educators should know about interim assessments.

Defining Interim Assessments

Typically, interim assessments are administered at different points during a school year (for example, in fall, winter, and spring) to measure how well students are learning a broad range of knowledge and skills. These assessments are shorter and more targeted than those used at the end of a school year. 

Educators usually deliver interim assessments within normally scheduled class time to help track academic progress and ensure students achieve specific learning objectives or grade-level milestones at the end of the year. 

How Are Interim Assessments Different from Summative and Formative Assessments?

The three most common types of assessments are summative, interim, and formative. While each type offers valuable information to educators, it’s critical to understand their differences to build a holistic assessment strategy. 

Summative and formative assessments can be defined as follows:

  • Summative assessments are typically administered at the end of a school year to measure student learning on a detailed set of standards. Many of these assessments, like ERB’s Comprehensive Testing Program (CTP), produce scaled scores and norms that educators can use to compare learning achievement for individual students and/or groups of students.
  • Formative assessments are briefer, more informal assessments that provide teachers with in-the-moment feedback on how well students have learned new material. While formative assessments may include short quizzes, they are often delivered using other formats, such as presentations, in-class activities, or online tools like ERB Writing Practice.

RELATED: How Different Types of Assessments and Measurements Help Inform Student Growth

To get a holistic view of the multiple factors that can foster or impede student growth, educators can leverage different types of assessment to track students’ academic achievement and well-being at school.

Interim assessments vary from summative and formative assessments in several key areas. Distinguishing features include:

  • Frequency: Interim assessments are typically administered two to three times a year, compared with once-a-year summative assessments and more frequent, often ad hoc formative assessments.
  • Purpose: Interim assessments give educators mid-year checkpoints on students’ overall progress, allowing them to address challenges, fine-tune curricula, and offer targeted support as needed. In comparison, formative assessments help educators track student attainment of specific skills, while summative assessments may carry higher stakes, such as final grades or advancement to the next grade level.
  • Content: Interim assessments typically fall between summative and formative assessments in scope. While formative assessments measure specific skills immediately after they’re taught, and summative evaluations track how well students have learned the material over an entire year, interim assessments more often measure progress on core skill sets such as reading and mathematics. 

Why Are Interim Assessments Valuable to Educators?

Interim assessments offer two primary advantages. First, since interim assessments are delivered at various points during the school year, they offer educators a chance to intervene and get students on track before it’s too late. Second, since interim assessments are delivered more than once per year to the same students, they provide tools to track progress and evaluate student growth in learning.

For example, if students across a class are demonstrating difficulty with understanding the concept of inference while reading, the teacher might modify their lesson plans to include additional in-class exercises on the topic. The next time they administer an interim assessment, they can see how that change affected results—and still have time to refine their strategy further before end-of-year summative assessments. 

Second, interim assessments also make it easier for educators to identify—and quickly respond to—challenges on the individual student level. 

“Suppose that a student’s reading performance has gone down dramatically,” says ERB Chief Program Officer Glenn Milewski. “That would be a clue a teacher could use to intervene with the student. What’s happening? Is the reading material getting too hard? Is the assessment measuring new skills like inference and understanding themes that students are struggling with? It gives educators clues before the period of learning is over, while they have time to intervene.”

Do Interim Assessments Lead to Overtesting?

While the benefits of interim assessments are clear, some school leaders, educators, and families may worry that they contribute to overtesting or an undue focus on “teaching to the test.” In reality, allocating a relatively small amount of time to targeted, high-quality interim testing can offer a disproportionate positive impact. 

ERB Milestones assessments, for example, were designed in partnership with member schools to help them maximize their real-time data without sacrificing instructional time or educator bandwidth. 

“We narrowed the focus to just reading and math and created a 40-minute test that would be manageable to administer in one class period in middle school or one part of the day in lower school,” Milewski says. “The burden of testing time is minimal for the value it delivers in tracking performance against norms and identifying specific skill areas that need attention.”

Interim Assessment in Action: ERB Milestones

To make the most of the data they collect, school leaders need high-quality assessments that offer actionable insights and reporting, and they must administer them at the right pace.

ERB designed its Milestones assessments for Grades 3-8 to measure foundational skills without impacting educators’ workloads or students’ stress levels. The assessments:

  • Focus on the skills educators find most critical—Reading Comprehension and Math
  • Are administered online to ensure score reporting in 24-28 hours
  • Take 40 minutes per topic

Schools can deliver Milestones as standalone assessments or in conjunction with ERB’s summative assessment, the Comprehensive Testing Program (CTP). The assessments are administered a maximum of three times a year (fall, winter, and spring) when used on a standalone basis or twice (typically fall and winter) when used in conjunction with CTP. That cadence gives educators three annual measurements of reading comprehension and math without overemphasizing testing. 

CTP and Milestones Testing Options

For schools that use Milestones with CTP, Milewski says, they get the best of both worlds—a summative test and complementary interim measures in reading and math. “The alignment of score scales, norms, and skill areas tested across these two types of assessments allow for apples-to-apples comparisons throughout the year,” Milewski says. 

Schools that utilize ERB’s Whole Child Solution can access reporting on Milestones and CTP alongside social-emotional learning data from the SelfWise inventory and data on student well-being from the Check-In Survey. Together, these data points help school leaders and educators provide comprehensive academic, social, and emotional support to help students grow and thrive in the school environment.


Used independently or paired with the CTP summative assessment, Milestones interim assessments serve as regular checkpoints throughout the year to provide data that inform instruction and support student growth.

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