SNAP-IV Scoring · Swanson, Nolan and Pelham ADHD Rating Scale

The SNAP-IV is a widely used parent and teacher rating scale for evaluating ADHD symptoms in children, and the screening scale recommended in Canadian (CADDRA) ADHD guidelines.

About the SNAP-IV

The SNAP-IV was developed by James Swanson, William Nolan, and William Pelham as a rating scale for the symptoms of attention-deficit/hyperactivity disorder and oppositional defiant disorder in children. The most commonly used short version, the SNAP-IV-26, draws its items directly from the DSM symptom criteria, so a clinician can map ratings onto recognised diagnostic domains.

It is completed by an adult informant who knows the child well — typically a parent and a teacher — because ADHD requires evidence of symptoms across more than one setting. Like the NICHQ Vanderbilt, the SNAP-IV is designed for school-aged children and is widely distributed, which has made it a standard tool in primary care, paediatrics, and school-based assessment across North America.

What does the SNAP-IV measure?

The SNAP-IV-26 covers three symptom domains:

• Inattention (items 1–9) — the 9 DSM inattention symptoms.
• Hyperactivity/Impulsivity (items 10–18) — the 9 DSM hyperactivity/impulsivity symptoms.
• Oppositional Defiant Disorder (items 19–26) — 8 ODD symptoms, screening for the most common ADHD comorbidity.

Longer versions of the SNAP add further comorbidity screens, but the 26-item form is the one most often used in routine practice.

How do you give the SNAP-IV?

The SNAP-IV is completed independently by the informant and takes about 10 minutes. Because DSM-5-TR requires symptoms in two or more settings, a valid ADHD screen uses both a parent and a teacher form. Non-clinical staff can administer the forms, but a licensed clinician must interpret them in the context of history, functional impairment, and other information.

How do you score and interpret the SNAP-IV?

How to score the SNAP-IV

Each item is rated on a 4-point frequency scale: 0 = Not at All, 1 = Just a Little, 2 = Quite a Bit, 3 = Very Much, reflecting the past month. Rather than a single summed total, each subscale is scored as an average: add the item ratings within a subscale and divide by the number of items in it.

There are two complementary ways to read the result:

1. Subscale average vs normative cut-point. Compare each subscale average with the informant-specific cut-point (below). An average at or above the cut-point places the child in the clinically significant range for that domain.
2. DSM symptom count. Count the items rated 2 (Quite a Bit) or 3 (Very Much) within the inattention and hyperactivity/impulsivity domains, mirroring the DSM threshold of six or more symptoms in a domain.

SNAP-IV cut-points at a glance

These are Swanson's normative 95th-percentile cut-points; they are informant-specific because teachers and parents rate differently. A subscale average at or above the relevant value indicates symptoms in the clinically significant range and supports referral for a full evaluation — it is a screening result, not a standalone clinical conclusion.

Psychometric properties

• US school sample. In parent (1,613) and teacher (1,205) ratings from a random sample of elementary school students, reliability was acceptable and the factor structure showed two ADHD factors and an ODD factor. Parent scores above 1.8 increased the probability of an ADHD diagnosis; teacher scores increased the probability of concern only ^[2].
• Swedish parent form. In 981 parents of 11-year-olds from a birth cohort, a three-factor model (inattention, hyperactivity/impulsivity, ODD) fit best with high internal consistency, and the inattention and hyperactivity/impulsivity subscales showed excellent classification accuracy for children diagnosed with ADHD ^[3].

Limitations

• Screening, not diagnosis. A positive SNAP-IV supports, but does not replace, a full clinical evaluation.
• Informant differences. Parent and teacher ratings often diverge; cut-points are informant-specific for this reason, and both perspectives are needed.
• Age range. The SNAP-IV is designed for school-aged children; for adults, use the ASRS, and for retrospective childhood symptoms in adults, the WURS-61.

SNAP-IV vs NICHQ Vanderbilt

The SNAP-IV and the NICHQ Vanderbilt are the two dominant DSM-aligned paediatric ADHD rating scales, both requiring parent and teacher informants.

• Vanderbilt. Adds a 1–5 performance/impairment subscale used directly in its positive-screen rule.
• SNAP-IV. Scored by subscale averages against normative cut-points.

Many Canadian clinics standardise on the SNAP-IV because it is the scale embedded in CADDRA guidance. For adult ADHD, pair with the ASRS.

Billing the SNAP-IV (CPT 96127)

SNAP-IV administration qualifies for reimbursement under CPT code 96127 (brief emotional/behavioural assessment) when scored and documented with clinical interpretation. Medicare's Medically Unlikely Edit caps 96127 at 4 units per date of service; commercial payer limits vary, so confirm your contract. When parent and teacher forms are both completed in the same encounter, each may be billed as a separate unit.