To calculate unscored interval IOA, divide intervals in which both observers scored nonoccurrence by intervals in which either observer scored nonoccurrence, then multiply by 100. The method focuses on agreement that behavior was absent and can be useful when occurrence is common. Report prevalence and overall disagreement because joint-occurrence intervals do not enter the calculation.

Define nonoccurrence

Use the same response definition, interval rule, access conditions, and valid exposure for both observers.

Build the nonoccurrence denominator

Include every interval where Observer A, Observer B, or both scored no occurrence.

Count joint nonoccurrence

The numerator contains only intervals where both scored absence.

Report complementary context

Show total intervals, occurrence prevalence, disagreements, and a method focused on occurrence when relevant.

Reconcile every interval before calculating

Use the same four-cell table as other binary interval methods: joint occurrence, joint nonoccurrence, Observer A only occurrence, and Observer B only occurrence. Preserve invalid or one-observer intervals in planned coverage without forcing them into the matched denominator.

Oren's eight-interval unscored denominator consists of six joint nonoccurrences plus two disagreements. The other four intervals are joint occurrences. All twelve matched intervals therefore reconcile as four joint occurrences, six joint nonoccurrences, and two one-observer disagreements.

Interpret absence agreement within prevalence

Unscored-interval IOA focuses on agreement when at least one observer recorded absence. Oren's result is 6/8 = 75%. Overall interval agreement is (6+4)/12 = 83.3%, while scored-interval agreement is 4/(4+2) = 66.7%.

A strong unscored result does not show that observers reliably detected occurrence. It is especially useful when behavior is common and agreement on absence is the harder question. Show occurrence prevalence, the complementary scored result when relevant, and which observer produced each one-sided score.

Use the formula and units for Oren

For Oren's unscored-interval IOA worksheet: unscored-interval IOA = intervals both observers scored nonoccurrence / intervals either observer scored nonoccurrence × 100. Keep observer records independent until both are locked. Preserve the matched exposure, raw observations, numerator, denominator, unrounded calculation, and final rounding.

Work the arithmetic for Oren

Oren's observers compare twelve intervals. At least one observer records nonoccurrence in eight intervals, and both record nonoccurrence in six. Unscored-interval IOA is 6 / 8 × 100 = 75%. The four joint-occurrence intervals do not enter this calculation.

Apply nonoccurrence-focused agreement to the decision

Oren's qualified clinician identifies the decision before choosing an agreement method or threshold. Compare a stricter or complementary method when prevalence, totals, or aggregation could hide relevant disagreement. Repair definitions, visibility, training, sampling, or matching before judging the implementer or client data.

Audit observer and sample conditions for Oren

Oren's record identifies observers, independence, training, recording mode, shared exposure, response definition, procedure version, observation coverage, missing pairs, reactivity, and disagreements. Consent, privacy, recording, employment, supervision, and payer rules remain separate requirements. Keep every open pair visible with an owner and next action.

Protect client access during Oren's observation

Oren's observation keeps AAC, interpreters, mobility, food, water, bathroom use, prescribed care, health support, rest, relationships, and emergency help available. Do not create extra distress or remove ordinary supports to obtain an agreement sample. Record when access, health, withdrawal, or observer presence changes the condition.

Ask five IOA questions for Oren

Use these questions in the unscored-interval IOA worksheet:

  • Did both observers independently score the same exposure, unit, definition, and condition?
  • Which calculation, numerator, denominator, prevalence, and rounding reproduce the result?
  • Which disagreements, missing pairs, invalid units, reactivity, or matching problems remain?
  • Which validity, treatment-integrity, client-outcome, experience, and access questions stay separate?
  • Which repair, complementary method, next sample, owner, and review date follow?

Keep raw observer records and disagreement types available.

Use current sources within their scope for Oren

For Oren's unscored-interval IOA worksheet, the BACB ethics hub points to current professional ethics materials. The CASP public summary provides high-level autism-treatment scope without licensed detailed procedures. The BACB Ethics Code addresses competence, client involvement, consent and assent when applicable, documentation, risk, supervision, and evaluation for covered behavior analysts. The BCBA Test Content Outline includes measurement, reliability, sampling, and data-based decisions as examination content rather than a case protocol.

For Oren, Vollmer, Sloman, and St. Peter Pipkin discuss practical implications of data reliability and treatment-integrity monitoring. Essig, Rotta, and Poling review IOA and fidelity reporting in an identified ABA research corpus. Reed and Azulay describe a calculation tool and agreement methods. ASHA says AAC users should always have access to their tools or devices. These sources do not create one universal IOA method or threshold.

Close Oren's agreement review

Ask Oren and the responsible clinician to review the unscored-interval IOA worksheet through accessible communication. Record the method, arithmetic, sample, disagreements, limits, measurement repair, selected decision, next observation, and review date. Reopen the analysis when the definition, observer, system, exposure, prevalence, client access, procedure, or decision changes.

Clinician release checklist

  • Do four joint occurrences, six joint nonoccurrences, and two disagreements sum to twelve?
  • Can another reviewer reproduce unscored agreement 6/8 = 75%?
  • Are overall 10/12 = 83.3% and scored 4/6 = 66.7% labeled as separate views?
  • Does the report explain why nonoccurrence agreement matters for this event prevalence?
  • Are missing intervals, disagreement direction, access conditions, and the next sample retained?

Related resources

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