What is the Conners test? The Conners 4 ADHD rating scales explained
The Conners test is an ADHD rating scale from MHS, now in its fourth edition (Conners 4), with parent, teacher, and self-report forms for ages 6 to 18. (151 chars)
Dr. Russell T. WarneChief Scientist
Share
The Conners test is a family of behavior rating scales that clinicians and schools use when evaluating children and adolescents for attention-deficit/hyperactivity disorder (ADHD). The current edition, the Conners 4th Edition (Conners 4), is published by Multi-Health Systems (MHS) and collects standardized ratings from parents, teachers, and the young person being evaluated. Parent and teacher forms cover ages 6 to 18, and the self-report form covers ages 8 to 18. This article explains what the Conners 4 measures, how its scores work, and why a rating scale is one part of an ADHD evaluation rather than a diagnosis by itself.
What is the Conners test?
The Conners scales are "norm-referenced" questionnaires, meaning a child's ratings are compared against ratings collected from a large standardization sample of same-age peers. The instruments have a long history: psychologist C. Keith Conners published a teacher rating scale for studying children's behavior in the American Journal of Psychiatry in 1969, and revisions of his questionnaires have been standard tools in ADHD research and practice ever since.
The modern editions are published by MHS, a Toronto-based assessment company. The Conners 3rd Edition (Conners 3) appeared in 2008, and MHS released its revision, the Conners 4, in 2022. According to the publisher, the Conners 4 provides "a thorough assessment of symptoms and impairments associated with ADHD" along with common co-occurring problems in youth aged 6 to 18. Administration and scoring are now fully digital through the MHS Online Assessment Center+, although paper forms can be printed and the responses entered online. Forms are available in English, Spanish, and Canadian French.
It helps to be precise about what kind of test this is. Unlike a performance test with tasks for the child to complete, the Conners 4 is a structured set of questions about how often specific behaviors occur, answered by the adults who see the child every day and, when the child is old enough, by the child as well.
Rater forms, ages, and length
A core design principle of the Conners scales is "multi-informant" assessment: the same child is rated by several people who observe them in different settings. The Conners 4 offers three rater forms.
• Parent form (ages 6 to 18): completed by a parent or guardian; the full-length version has 117 items.
• Teacher form (ages 6 to 18): completed by a teacher who knows the student; the full-length version has 109 items.
• Self-report form (ages 8 to 18): completed by the child or adolescent; the full-length version has 118 items and is written at about a third-grade reading level.
Each rater type comes in three lengths. MHS reports that the full-length forms take about 12 to 15 minutes, the short forms (roughly 50 items) take 5 to 7 minutes, and the Conners 4–ADHD Index, a 12-item screener built from the items that best distinguish youth diagnosed with ADHD from the general population, takes under 2 minutes.
Comparing informants matters because ADHD symptoms must show up in more than one setting. A child rated as highly inattentive at school yet unremarkable at home presents a different clinical picture from one whose ratings are elevated everywhere, and that discrepancy is itself useful information.
What the Conners 4 measures
The full-length Conners 4 is organized into several groups of scales. The publisher's overview materials describe the following structure.
• Content scales: six scales covering Inattention/Executive Dysfunction (trouble focusing, sustaining, and shifting attention, plus self-management), Hyperactivity, Impulsivity, Emotional Dysregulation (difficulty managing emotions), Depressed Mood, and Anxious Thoughts. The executive function content reflects the well-documented overlap between ADHD and difficulties with planning and self-regulation, and the emotional scales capture problems that commonly travel with ADHD.
• DSM symptom scales: items keyed directly to the diagnostic criteria in the "DSM" (the Diagnostic and Statistical Manual of Mental Disorders) for ADHD inattentive symptoms, ADHD hyperactive/impulsive symptoms, total ADHD symptoms, oppositional defiant disorder, and conduct disorder.
• Impairment and functional outcome scales: ratings of how much the symptoms interfere with schoolwork, peer interactions, and family life. These replaced the Conners 3 Learning Problems, Peer Relations, and Family Relations scales.
• Critical and indicator items: brief item sets flagging self-harm concerns, severe conduct problems, and possible sleep problems so the evaluator can follow up.
• Response-style checks: indices that flag possible exaggeration, inconsistent or careless responding, omitted items, and unusually fast completion.
The Conners 4 also added a severity feature: a child's results can be compared not only with the general population but with an "ADHD Reference Sample" of youth already diagnosed with ADHD, which helps describe how severe the reported symptoms are relative to clinical peers.
How Conners scores work: the T-score metric
Conners results are reported as "T-scores". According to the Conners 4 manual, all T-scores have a mean of 50 and a standard deviation of 10, and they are computed relative to the normative sample for the child's age (with gender-specific norms available as an option). The Conners 4 norms are based on 3,120 youth across the parent, teacher, and self-report samples in the United States and Canada.
The manual groups T-scores into interpretive bands: scores of 70 or above are labeled Very Elevated, 65 to 69 Elevated, 60 to 64 Slightly Elevated, 40 to 59 Average, and below 40 Low. Higher scores indicate more marked symptoms or impairment as seen by that rater. Because every score contains measurement error, careful evaluators read scores near a cutoff cautiously and look at the pattern across raters rather than fixating on a single number. A teacher T-score of 66 on Inattention/Executive Dysfunction is a signal worth investigating, and it means considerably more when the parent and self-report forms tell a similar story.
Note that this is a different scale from IQ scores, which use a mean of 100 and a standard deviation of 15. A Conners T-score of 70 is high (about two standard deviations above the mean), while an IQ score of 70 is low (two standard deviations below the mean). Confusing the two metrics is common when reading evaluation reports.
How the Conners test fits into an ADHD evaluation
A frequent misunderstanding is that a Conners score by itself equals an ADHD diagnosis. The publisher is explicit that it does not. The Conners 4 manual states that rating scale data alone are not sufficient for making an ADHD diagnosis, and that the instrument "is not by itself a diagnostic tool"; it informs diagnosis with norm-referenced data that must be combined with interviews, observations, record reviews, and other testing.
Clinical guidelines say the same thing. In its 2019 clinical practice guideline, the American Academy of Pediatrics directs clinicians to determine that full DSM-5 criteria are met, including documented symptoms and impairment in more than one major setting, using information obtained primarily from parents or guardians, teachers, and other school personnel, and to rule out alternative causes such as sleep disorders, learning problems, or other mental health conditions. Rating scales such as the Conners 4 are the standard way to gather that multi-setting information, and they quantify how unusual a child's behavior is for their age. The diagnosis itself rests on the clinician's integration of the full picture.
In fuller evaluations, the ratings are often paired with cognitive testing, such as an IQ test like the WISC (see our guide to what the WISC test measures), academic achievement measures, and sometimes a broader neuropsychological battery. Our overview of what neuropsychological testing involves explains how those pieces fit together. Cognitive testing likewise cannot diagnose ADHD; its role is to rule out other explanations for school struggles and to identify strengths and weaknesses that shape recommendations.
For adults, MHS publishes a separate instrument, the Conners Adult ADHD Rating Scales, updated in a second edition in 2022.
Conners scores and IQ scores measure different things
ADHD and intelligence are distinct constructs. A Conners form asks how often behaviors occur; an IQ test measures reasoning ability directly under standardized conditions. People with ADHD span the full range of intelligence, and a high Conners score says nothing about how smart a child is. Our article on how ADHD relates to IQ scores covers the research on that relationship in detail, including why attention problems can nudge some scores downward without changing underlying ability.
For adults who want a clear reading of their cognitive ability, the RIOT IQ test (the Reasoning and Intelligence Online Test), developed by RIOT IQ with psychometrician Dr. Russell T. Warne, measures intelligence in adults 18 and older with 15 subtests across six cognitive indices: verbal reasoning, fluid reasoning, spatial ability, working memory, processing speed, and reaction time. It takes about 52 minutes and reports scores on the familiar mean-100, standard-deviation-15 IQ scale. It is an ability measure rather than an ADHD assessment, and it does not replace an individually administered diagnostic evaluation. If you would like a rigorous picture of your reasoning skills alongside any attention concerns you are exploring, you can take the RIOT IQ test at riotiq.com.
FAQ
Is the Conners test used to diagnose ADHD?
It contributes to a diagnosis but cannot make one alone. MHS states that rating scale data by themselves are not sufficient; guidelines require full DSM-5 criteria, information from multiple settings and informants, and ruling out other causes.
What ages does the Conners 4 cover?
Parent and teacher forms cover ages 6 to 18. The self-report form, completed by the young person, covers ages 8 to 18. Adults are assessed with a separate instrument, the Conners Adult ADHD Rating Scales.
What is a high score on the Conners test?
Conners results are T-scores with a mean of 50 and a standard deviation of 10. The manual labels 60 to 64 Slightly Elevated, 65 to 69 Elevated, and 70 or above Very Elevated relative to same-age peers.
What is the difference between the Conners 3 and the Conners 4?
The Conners 4 (2022) is the revision of the Conners 3 (2008). It moved to fully digital scoring, added Emotional Dysregulation, Depressed Mood, and Anxious Thoughts scales, added a sleep indicator and self-harm items, and converted the old Learning Problems, Peer Relations, and Family Relations scales into impairment measures.
How long does the Conners 4 take?
MHS reports about 12 to 15 minutes for the full-length form, 5 to 7 minutes for the short form, and 1 to 1.5 minutes for the 12-item ADHD Index.
Does the Conners test measure IQ?
No. It rates the frequency of ADHD-related behaviors and impairment. Intelligence is measured with separate cognitive tests, and a child's Conners score does not indicate their IQ.
6. Wolraich, M. L., Hagan, J. F., Allan, C., et al. (2019). Clinical practice guideline for the diagnosis, evaluation, and treatment of attention-deficit/hyperactivity disorder in children and adolescents. Pediatrics, 144(4), e20192528. doi.org
7. Conners, C. K. (1969). A teacher rating scale for use in drug studies with children. American Journal of Psychiatry, 126(6), 884-888. doi.org
[Hero image credit line to be added at staging once the licensed photo is selected.]
Hero photo: an adult filling out pages on her lap at home. Photo by Kristin Hardwick via Wikimedia Commons / ISO Republic, CC0 (https://creativecommons.org/publicdomain/zero/1.0/), cropped.
Take our professional IQ test
Want to know your IQ? Try the first ever professional online IQ test.
