Assessment Literacy Video Series: Understanding Scale Scores

Making sense of assessment data can be complicated—we’re here to break it down so that reading your reports doesn’t require a translator. Let’s look at scale scores—the underlying way assessment performance is often reported.

Defining Scale Scores

Have you ever looked at your student’s scale score and seen something like 950 and thought what do I do with this? This is a scale score—and no, it’s not on your plain 0–100 percent scale. But, there IS a reason for that, and once that reason is made clear, you’ll love scale scores as much as we do (OK, maybe not, but we’ll give it a shot).

Without scale scores, your students may feel like this:

A student might say, “On my last math test, I got 86 percent. This time, I got 84 percent, but the questions were a lot harder. I thought I learned so much in math. What went wrong? Why did my score go down?”

When tests are scored simply on the percent or number of questions correct, it’s difficult to compare performance on one test to another because one test may have harder questions. That’s where scale scores come into play.

Scale scores are like holding a yardstick up to a student to measure ability and then being able to use that same yardstick year after year with all of your students. With a scale score, which is typically a three- or four-digit number, you can compare performance from the same test given at different times both within a school year and across grade levels to show student growth. Of course, math would not be on the same scale as reading because they measure different things.

For example, a student with a scale score of 900 in 4th grade and a scale score of 950 in 5th grade showed 50 points of growth. When students participate in the same testing program where a single scale is used to measure everyone, scale scores can also be used to compare students from different classes and schools.

How a Scale Is Built

Interested in the more technical side of how to build a scale like this in the first place? Check this out. Scale scores are created through a method called scaling. A student’s scale score will go up as the student learns and grows academically. First, every test question is tried out in a carefully planned research design where some students answer the same questions as each other, and to get the scale to extend across grades vertically, some students might answer questions from one grade level below their own grade. This tells us how difficult each question is relative to the other questions. Then, when a student takes a test, the scale score reflects the difficulty of questions the student answered correctly. Students that answer more difficult questions correctly will have a higher scale score. Many tests use scale scores. Although the specific numbers of the scale are different for different testing programs, scale scores are built essentially in the same way.

Scale Scores in Exact Path

Edmentum Exact Path, our K–12 program that combines adaptive diagnostic assessments with individualized learning paths, uses scale scores! In this program, after a student completes their diagnostic assessment, they receive a scale score. In our program, the range of this scale is from 500 to 1500, and you’ll find it in a series of our diagnostic reports.

Let’s look at one student over time through all their assessment administrations this year. As the student learns both in the classroom and through a program like Exact Path, we would expect them to be able to successfully answer more difficult questions, earning a higher scale score and, ultimately, allowing us to quantify growth.

Another huge benefit of using scale scores is comparability. Let’s compare that student’s score to the whole class or grade level. When we look at all students’ scores in this class, we see that Amy scored a 755 on her spring math assessment, but most of her peers scored in the low 600s and 700s. That means that Amy is more advanced in math compared to her peers.

Now, you understand the power of scale scores! By taking into account the difficulty of the questions a student answered, scale scores allow educators to measure growth and to compare students to one another—even students in different grades—by using the same yardstick for everyone.

Interested in learning more about how to boost your students' test performance? Explore proven tips and tricks for effective assessment preparation.