To compare IOA across ABA settings and conditions, stratify the results by setting, partner, task, support availability, response form, and procedure version. Preserve each numerator, denominator, method, and coverage measure. A percentage difference can reflect sample size, prevalence, visibility, access, or definition use. Review those conditions before attributing the pattern to an observer or setting.
Predeclare strata
Choose clinically relevant conditions before seeing the results. Avoid slicing until a preferred pattern appears.
Hold the method stable
Use the same response definition, unit, calculation, and missing-data rule or label the comparison as non-equivalent.
Record access and visibility
Include AAC, interpreters, mobility, distance, noise, partners, and line of sight.
Keep small samples visible
Report raw counts, dates, range, and pending observations for every stratum.
Build one comparable row per condition
For each setting or condition, record the response definition, IOA method, eligible unit, observer pair, exposure, procedure version, staff, supports, access state, and date range. Add planned, observed, shared-valid, and excluded counts. Comparisons become interpretable only when the rows describe the same measurement question.
If the method or unit changes, place the result in a separate table. A total-count percentage and trial-by-trial agreement answer different questions. The same caution applies when one setting uses ten-second intervals and another uses whole-session counts.
Reconcile Gia's condition table
Gia's numerators total 18 + 7 + 4 = 29 agreements across 20 + 10 + 8 = 38 matched trials. A weighted pooled result would be 29 of 38, or 76.3%. Keep the center's 90%, home's 70%, and community's 50% beside that pooled value. The pooled number gives the largest sample the greatest influence and conceals the condition that most needs review.
The community result changes by 12.5 percentage points with one trial because its denominator is eight. That sensitivity, greater movement, and the AAC visibility problem all matter. Collect another representative sample after repairing visibility and preserve the original community result.
Examine plausible measurement explanations
Review line of sight, movement, noise, crowding, observer position, response opportunities, partner behavior, device access, timing, and event prevalence. Check whether the same observer pairs worked across settings. A lower result may reflect a harder-to-observe response, a different opportunity mix, missing support, or a definition that fits one context poorly.
Ask Gia how the observation and communication setup worked in each location. Client experience may reveal access or privacy differences that the IOA percentage does not capture.
Apply the field control to one defined question
The condition-stratified IOA table for Gia begins with the exact decision, the responsible qualified role, and the evidence needed. Preserve original observer records, matched exposure, the selected calculation, raw numerator and denominator, unrounded result, and every excluded or unresolved unit.
Work the example for Gia
Gia's matched-trial results are 18 of 20 at the center, 7 of 10 at home, and 4 of 8 in the community: 90%, 70%, and 50%. The community sample also has more movement and one AAC visibility problem. These figures identify a review priority without establishing a setting effect.
Audit the denominator for Gia
The denominator for Gia is the eligible cohort defined before review. Report planned, due, observed, matched, invalid, missing, and open units separately. A percentage gains meaning from the unit, coverage, dates, conditions, and disagreement pattern.
Protect access and safety during the sample for Gia
The observation for Gia keeps AAC, interpreters, mobility, food, water, bathroom use, prescribed care, health supports, rest, relationships, and emergency help available. Observer procedure never delays immediate safety or mandated action. Record changes in access, health, assent, distress, visibility, staff behavior, or routine.
Use current sources within their scope for Gia
For Gia, the BACB ethics hub points to current ethics materials. The CASP public summary supplies high-level autism-treatment scope. The BACB Ethics Code addresses competence, client involvement, consent and assent when applicable, documentation, supervision, risk, and evaluation for covered behavior analysts. The BCBA Test Content Outline includes measurement, reliability, sampling, and data-based decisions as examination content.
For Gia and the condition-specific IOA question, 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 research corpus. Reed and Azulay describe agreement calculations and a calculation tool. ASHA says AAC users should always have access to their tools or devices. The responsible clinician still selects a case-specific measurement and review plan.
Close the IOA review for Gia
Review the condition-stratified IOA table with Gia through accessible communication and with the responsible clinician. Record the question, sample, method, arithmetic, disagreement types, limits, repair, owner, next observation, and review date. Reopen the review when the definition, observer, setting, system, exposure, access, prevalence, procedure, or decision changes.
Before release, verify that strata were declared in advance, methods are equivalent, and every raw count remains visible. Record repairs and schedule follow-up in the condition with the weakest or least representative evidence. Treat differences as measurement signals until replicated evidence supports a broader interpretation.
Related resources
- How to Interpret IOA Thresholds Without a Universal Cutoff
- How to Analyze IOA by Observer Pair
- How to Investigate Low IOA in ABA Data
- How to Handle Partially Observed Sessions in IOA
Sources
- Behavior Analyst Certification Board, Ethics Codes
- Council of Autism Service Providers, ABA Practice Guidelines Version 3.0 public summary
- Behavior Analyst Certification Board, Ethics Code for Behavior Analysts
- Behavior Analyst Certification Board, BCBA Test Content Outline, 6th edition
- Vollmer, Sloman, and St. Peter Pipkin, Practical Implications of Data Reliability and Treatment Integrity Monitoring
- Essig, Rotta, and Poling, Interobserver Agreement and Procedural Fidelity: An Odd Asymmetry
- Reed and Azulay, A Microsoft Excel 2010 Based Tool for Calculating Interobserver Agreement
- American Speech-Language-Hearing Association, Augmentative and Alternative Communication