Conners 3 Rating Scale · Scoring & T-Score Interpretation

The Conners Rating Scales are the criterion standard for ADHD assessment in children and adolescents (ages 6–18). Parent, teacher, and self-report versions measure inattention, hyperactivity/impulsivity, and executive function. A T-score of 65 or above indicates clinical concern. Conners (2008).

Assessing an adult? See the CAARS (Conners Adult ADHD Rating Scale).

Looking for the Conners CPT-3? This page covers the Conners 3 Rating Scale, a questionnaire completed by parents, teachers, and youth. The Conners CPT-3 (Continuous Performance Test) is a separate computerized attention task administered directly to the patient. Both are published by MHS.

What the Conners 3 measures

The Conners Rating Scales, developed by C. Keith Conners and published by Multi-Health Systems (MHS), are among the most widely used standardized rating-scale systems for assessing ADHD and related behavioural, emotional, and academic problems in children and adolescents. The current edition, the Conners 3rd Edition (Conners 3), published in 2008, provides updated norms and expanded coverage of executive functioning and comorbid conditions.

Content scales

The Conners 3 reports six content scales:

• Inattention — difficulty sustaining attention, careless errors, disorganization.
• Hyperactivity/Impulsivity — restlessness, difficulty waiting, acting without thinking.
• Learning Problems — academic difficulty in reading, math, or spelling.
• Executive Functioning — trouble starting, planning, and completing tasks.
• Defiance/Aggression — argumentativeness, rule-breaking, or aggressive behaviour.
• Peer Relations (and Family Relations on the self-report) — difficulty with social or family relationships.

How to administer the Conners 3

The Conners 3 includes three parallel forms: a Parent report (about the child, completed by a parent or guardian), a Teacher report (completed by the classroom teacher), and a Self-Report (completed by the youth, ages 8–18). Each form is available in full-length and short versions. Using multiple informants across settings is a key advantage — under DSM-5-TR, ADHD symptoms must be present in two or more settings.

The Conners 3 is purchased from MHS and is intended for use by qualified professionals — typically psychologists, physicians, or other clinicians trained in psychological assessment. During active treatment it is commonly repeated at baseline and then every 4–8 weeks to track response.

Conners 3 scoring and interpretation

Scores are reported as T-scores normed to age and gender (mean = 50, SD = 10). Use the interpreter above to translate a T-score into its interpretive band:

• T ≥ 70 — Very Elevated (about the 98th percentile and above).
• T 65–69 — Elevated (about the 93rd–97th percentile); clinically significant, warranting further assessment.
• T 60–64 — High Average.
• T < 60 — Average / Not Elevated.

Interpretive ranges follow the Conners 3 manual. Scoring and interpretation should be performed by a trained administrator within an appropriate clinical context.

How ADHD Is Diagnosed (DSM-5-TR)

The Conners 3 informs, but does not replace, a diagnostic evaluation. A full ADHD evaluation integrates Conners 3 ratings across parent and teacher forms with a clinical interview, developmental history, medical evaluation, and direct observation. Under DSM-5-TR, a diagnosis requires at least six inattention symptoms or six hyperactivity/impulsivity symptoms (five or more per domain for individuals aged 17 and older), present in two or more settings, with several symptoms emerging before age 12 and clear evidence of functional impairment.

Psychometric properties

Hardly any peer-reviewed studies report Conners 3 psychometrics beyond the test manual itself (Christiansen et al., 2016). In a German validation (745 children, 953 parents, 741 teachers; ages 6–18), confirmatory factor analyses showed very good model fit with highly satisfying internal consistency (Cronbach's α), although exploratory factor structures differed from the American model. In an Italian sample (591 youth, 631 parent and 325 teacher ratings), the Conners 3 short forms reproduced the original multidimensional structure and were reliable and valid for assessing ADHD and its main comorbid conditions (Izzo et al., 2019). Its predecessor, the revised teacher scale (CTRS-R), correctly classified 85% of children with ADHD versus typically developing children, with generally satisfactory test-retest and internal-consistency reliability (Conners et al., 1998).

Limitations

• Not a diagnosis. The Conners 3 informs, but does not replace, a full diagnostic evaluation.
• Rater perspective. Parent, teacher, and self-report ratings reflect each informant's view and can disagree; ratings from one setting cannot establish the cross-setting requirement on their own.
• Norm dependence. T-scores compare a child with the normative sample; cross-cultural use needs local validation, and factor structures have differed in translated versions (Christiansen et al., 2016).
• Licensed. The forms and manual are purchased from MHS and require a trained administrator.

ADHD Outcome Monitoring in HiBoop

HiBoop does not offer the Conners 3; this page is reference material. For ADHD, HiBoop offers the NICHQ Vanderbilt, SNAP-IV, SWAN and WFIRS-S, scored on submission and tracked over time.