skip to Main Content

Decoding Norm-Referenced Assessments

When a child is referred for evaluation in the schools or as new client in the clinic, one of the most important and frequently used tools is norm-referenced testing. Norm-referenced testing can also be useful when re-evaluating a child by comparing previous and present scores to get a sense of their progress. However, if you and your child are new to speech, occupational, or physical therapy services, understanding the meaning of norm-referenced scores on evaluation reports can be quite confusing. This post will explain how norm-referenced assessments are used, break down some of the jargon, and discuss some of the limitations of norm-referenced testing.

What is a norm-referenced test?

A norm-referenced test is a type of standardized assessment, meaning that all test items are required to be answered and scored in the same manner.  Norm-referenced tests compare a child’s performance to a normative sample. What is a “normative sample”? During test design, the test creators administer the assessment to a large group of children (usually hundreds to thousands) from varying regions, socioeconomic backgrounds, races, and disability statuses that are intended to represent the general population of children for whom the test is intended. Each test taker’s performance is then ranked according to age group and/or sometimes gender along the bell curve, pictured below. Individuals who fall in the middle of the curve are considered to be typical or “average” for that peer group. Children who fall to the right of center would be considered to be above average, while children who obtained scores that place them to the left are considered below average compared to peers. When your child takes a norm-referenced test, their score is compared to the normative sample to determine where they fit in amongst their peers on the curve, which helps us see if their abilities are typical for their age group.

Terms you may see on an evaluation report and what they mean:

Standard Score

When a child completes a norm-referenced test, the clinician takes their raw score (the number of test items they answered correctly) and converts it into a standard score, which corresponds to the bell curve. Standard scores between 85 and 115 are considered to fall in the average range. If a child obtains a standard score less than 85, this is considered below average and may indicate skill deficits or impairment compared to others their age.

Percentile Rank

Standard scores can be compared to come up with a percentile ranking. Percentile rank indicates the percentage of same-age peers that scored the same or lower than the child who is being evaluated. For example, if a child scores in the 40th percentile, this means they scored as well or better than 40% of other same-age peers who took the test. It is important to keep in mind that percentile has nothing to do with percentage correct. Percentile ranks below 16 are considered to fall below average.

Confidence Interval

Because human behavior is variable, we can never be 100% certain whether a child’s performance is due to their actual skill base or other factors (attention, motivation, memory, etc.). To account for this uncertainty, many clinicians report a Confidence Interval, which indicates a score range where we are highly certain the child’s true score lies. For example, if a child receives a standard score of 79 with a 90% confidence interval of plus or minus 5, then we are highly certain the child’s true score lies between a standard score of 74 and 84.

Standard Deviation

Standard deviation tells us how far a standard score differs or “deviates” from the mean. On the bell curve, the mean standard score is always 100, which falls in the exact center. The closer a child’s score is to 100, the smaller the standard deviation. One standard deviation above or below the mean is 15, giving us the 85 to 115 range discussed earlier. A child who scores greater than one standard deviation below the mean would fall in the “below average” range compared to same-age peers clinically, though some school districts require students to fall at least 1.5 or 1.75 standard deviations below the mean to be eligible for special services.

When norm-referenced tests aren’t enough

Although norm-referenced tests are an important tool for helping clinicians diagnose disorders, they are not perfect. Some norm-referenced assessments have design flaws that affect how accurate they are or whether they actually test the skills we are interested in. In addition, normative samples don’t always reflect the background of the child being evaluated, creating “unequal” comparison. There are also factors individual to the child that may come into play. Although a norm-referenced test may be appropriate for a child based on their age, the child’s true abilities may not be captured by a norm-referenced test if they have trouble engaging in structured tasks or have physical and/or cognitive barriers that would make it difficult to complete the test. Because of these limitations, clinicians rely on other assessment tools, such as observations, parent and/or teacher input, and schoolwork samples. This way we can ensure we have a complete picture of a child and can develop an intervention plan that will meet their specific needs.

-Olivia Edelman, M.A. CF-SLP

Back To Top

Patient Reviews

LLA Therapy

Patient Reviews

Crystal Scheibe

Great place, glad we found them. Been going to Medina over 2 months now and he loves Lauryn and Kyler. Wish they had more ABA therapy places available... live in Wooster and long drive everyday.

Karrie Swan LaRock

My 11 year old son has dyslexia and has made noticeable gains in working At LLA THERAPY. Katie is strong in her approach toward him and also keeps him comfortable enough to perform well. We will continue visiting both the Fairlawn and Hudson offices and recommend them highly.

Ron Monroe

My 9 year old just completed about 9 months of weekly speech sessions (due to his stuttering) with Matt Hagge at LLA and we are thrilled with the experience and results. What I thought might be a negative (what kid really wants to go to speech class?) was made very positive by Matt, and my son never hesitated or complained when we talked about class. He really enjoyed it and really took what Matt taught him to heart. His speech has been greatly improved and we definitely recommend LLA. Thank you so much!

Heather Dougherty-Pantoja

My son’s Occupational Therapist, Jess, is an amazing OT! She gives practical tips on working with my son at home and school!

Terri Apgar

I cannot say enough good things about LLA Therapy. My daughter was a client of Teal Simmons’ for approximately 2 years and was just released from speech therapy! She was diagnosed with Apraxia in 2015 and worked with Teal twice a week. Through Teal’s application of PROMPT therapy, my daughter had age-appropriate speech after one year. All of the staff we interacted with at LLA were absolutely wonderful. They really care about what they do and making sure your child achieves their goals.

Kelli Geisler Davisson

LLA Therapy has been an excellent experience for my son as well as my family! My son always asks, "When can I go see Ms. Jeannine again, is it Monday??" He has also made huge gains in only 5 months! I would highly recommend LLA and have already shared my experience with friends looking for services!

Victoria Hansford-Price

We are so grateful for our Speech Therapist Ms.Teal. We have seen a great improvement with our sons confidence and communication abilities since we have started "Prompt" therapy. What we love the most about LLA and Ms. Teal is that Kohl feels comfortable and relaxed which has played a critical role in his progress. Thank you Ms. Teal for all you have done.

Laura Lee Hogsett

They have helped in numerous ways. Speech, OT and behavioral. I've had numerous compliments on my son's progress thanks in very large part to LLA. I would recommend LLA before I recommend our local children's hospitals, though they are good, they don't have the staff that LLA does.

Amy Furukawa

We had a great experience with Matt Hagge at LLA! Our Middle School age son was becoming very conscious of his voice, which is nasal due to a cleft palate. Matt helped him to better form his sounds and project his voice in a way that makes the unavoidable nasality less noticeable.Our son is more confident and outgoing & even took on a speaking role in the church play. Matt has the perfect personality to relate with our son, and we would recommend him to anyone needing speech therapy services!

Jessica Havalotti

LLA Therapy has been an excellent experience for our daughter. I would highly recommend LLA. Miss Grace was so amazing and I can't believe how quickly our daughter showed improvement. Thank you!
Read More