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

The SNAP-IV is a free, 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 freely available, which has made it a standard tool in primary care, paediatrics, and school-based assessment across North America.

What the SNAP-IV Measures

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.

SNAP-IV Scoring & Interpretation

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.

Administration

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.

Psychometric Properties

The SNAP-IV's three-factor structure (inattention, hyperactivity/impulsivity, ODD) has been confirmed across language versions, with high internal consistency and good criterion validity for identifying children with a clinical ADHD diagnosis (Bussing et al., 2008; Tallberg et al., 2025). Receiver-operating-characteristic analyses support strong classification accuracy for the inattention and hyperactivity/impulsivity subscales.

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 free, DSM-aligned paediatric ADHD rating scales, both requiring parent and teacher informants. The Vanderbilt adds a 1–5 performance/impairment subscale used directly in its positive-screen rule; the SNAP-IV is 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. The AMA allows up to 4 units per encounter; Medicare limits this to 3. When parent and teacher forms are both completed in the same encounter, each may be billed as a separate unit.