“I need to know if my students are learning.” Sound familiar? We hear it a lot, and if you’re an educator, you’ve likely not only heard it, but said it as well. But measuring growth is only useful if it’s done well. It’s not about just comparing one proficiency score to the next one. It’s about accurately identifying each student’s current performance level—with the same precision for students well above or well below grade level as for those in the middle of the pack.

Educators on the front lines have long understood that each student is unique—with their own talents, challenges, and ways of learning—and that to apply the same one-size-fits-all approach to an entire population is bound to leave many kids behind. Grade-level proficiency measures might assess kids in the middle well, but they might leave other students behind entirely—any kid working above or below grade level in any subject is underserved by such tests. Measuring growth is valuable because it gives teachers information that helps them support learning for every student, regardless of their proficiency status.

Over the next two blogs, we’ll dive into seven features that make up a great growth measure. Having measured growth for more than 40 years, the researchers and educators here at NWEA are dedicated to validating the best growth measures and sharing these crucial criteria for a great growth assessment.

1. The test should be based on your educational standards. Each state has a set of educational standards that describe exactly what students should learn in every grade. Your curriculum plans are based on these standards. You teach students the content described in the standards, and you teach it in the order laid out by the standards—from early foundations for young children all the way to the most advanced ideas for teens.

So for your assessment to be useful, it needs to measure students’ academic growth in gaining the knowledge described in your standards—as well as the level of understanding the student has achieved.

2. The test should use a scale with equal intervals over time. Imagine you measure your daughter’s height at the beginning of the year and discover she’s 4’3″ tall. You measure her at the end of the year and discover she’s 1.35 meters tall. Has she grown? It’s impossible to tell by comparing those two numbers, because you used a different scale—feet and inches versus meters—each time you measured. In this case, you can translate meters into inches because there’s a known relationship between those two scales. But what if you’d measured her once in ancient Egyptian cubits? There’s no way to translate that ancient measurement system into modern inches or meters.

This illustrates the importance of using the same scale over the entire time you’re assessing progress. That’s how you can see if someone has grown—you measure once, measure again later, and compare the results. The difference is the amount of growth. And, crucially, that measurement must take into account more than proficiency—it must truly identify a student’s performance (regardless of grade level) and show their full learning progression.

In addition, you need your scale to use equal intervals over time, because that’s what allows you to not just measure growth, but also see how that growth changes over time. After measuring student performance multiple times, you want to know not just how much a student has grown between measurements, but details about that growth—is the student growing more slowly now than they were last year? Is she growing faster? About the same? This detail tells you important information about a student’s learning progression and lets you know if you need to intervene now—before she’s fallen behind.

So in order to give you a valid answer to “has this student grown, and how much?” your test should have a scale that uses the same equal intervals for every grade, from pre-kindergarten all the way through twelfth grade.

3. The test should measure a student’s performance correctly, regardless of their grade. Let’s go back to the metaphor of measuring height. Say you want to quickly and easily learn the height of every kid in a big third grade class, so you buy a new high-tech gadget that can digitally scan the group and detect their heights. But this magic device has one limitation: it can only detect heights between 4′ and 4’6″. Sure, most of the kids in your class will fall in that range, but the fact is, there are sure to be some extra-short kids and some especially tall kids who just don’t fit in. If you go ahead and use that measuring tool, you won’t have any clue how tall the shortest and the tallest kids are—so you certainly can’t measure their growth over time.

The same is true with academic measurement. If your test is only measuring whether your third graders have mastered third-grade skills, it won’t tell you anything at all about the kids who are still struggling with second-or even first-grade skills. And it sure can’t give you any useful information about the high-flyers who are working at a fifth-grade level.

If you aren’t measuring those students, you can’t understand what they know and need to be taught next. You won’t know if they’ve hit a wall in their learning, if they’ve missed out on a key concept, or if they’ve exhausted the challenges before them and are spinning their wheels.

Equity in the classroom demands an assessment that accurately measures the growth of every student, regardless of the grade level they happen to be in.

We believe measuring growth is the key to helping students learn, which is why our flagship interim assessment—MAP® Growth™—was built specifically with this purpose, and has been continually refined over the decades to deliver the highest quality data in the industry. Our next post will round out the seven crucial criteria for a great growth assessment, so be sure to check back soon!