Single-case overlap with a trend change means some values from adjacent phases occupy the same range while the direction of the data path changes. Report the overlapping values and denominators, then describe each phase's trend, level, variability, and boundary pattern. Overlap can temper a claim about separation. It does not erase a potentially meaningful slope change, which still needs replication and contextual review.

Define overlap before calculating

State whether overlap means shared exact values, points within a phase range, or a named metric with its own reference rule.

Show both phase directions

Plot and describe slopes or data paths in original units, including whether the baseline trend was therapeutic or countertherapeutic.

Keep the boundary visible

Report the last baseline and first intervention observations separately from the full phase patterns.

Avoid one-feature verdicts

Neither overlap nor slope alone establishes the overall effect. Integrate all visual features and measurement quality.

Look for replicated departures

Ask whether trend changes recur at planned condition changes across tiers or phases and whether competing events align with them.

Build Noor's overlap-and-trend comparison

For the single-case overlap with trend change question, create a versioned overlap-and-trend comparison. Preserve the target definition, unit, opportunity or observation time, raw series, graph, phase boundaries, design logic, predicted changes, planned demonstrations, actual implementation, measurement quality, client input, access and safety evidence, context, reviewer judgments, and claim status. The record should let another qualified reviewer reconstruct Noor's evidence without relying on a summary score.

Work through Noor's replication example

Noor's baseline values are 4, 6, 8, 10, and 12, an upward pattern for a measure where lower is preferred. Intervention values are 10, 9, 8, 7, and 6, a downward pattern. Three of five intervention values, 10, 8, and 6, fall within the exact baseline value set, while the direction clearly reverses. Display every value, phase, denominator, and time sequence. This fictional school task-completion study example illustrates one evidence pattern and does not establish a universal phase length, effect threshold, functional relation, treatment recommendation, or review outcome.

Audit Noor's design evidence

Noor's worksheet reports three of five exact-value overlaps under its declared definition, plots both trends, preserves the boundary values 12 and 10, and records equal observation conditions. It avoids concluding no effect from overlap alone or a functional relation from slope reversal alone. The audit also checks graph axes, session spacing, invalid and missing states, implementation fidelity, condition discriminability, carryover, definition changes, concurrent events, software settings, and correction history. A missing field does not become a negative value or disappear from the denominator.

Address Noor's main inference risk

Different overlap metrics use different reference rules, and exact-value matching is only one descriptive choice. Noor's page names the rule and keeps the graph visible so a percentage cannot obscure trend, time order, or scale. Reviewers describe the raw pattern first, then the narrower conclusion it supports. A clinical improvement can be real and valuable even when the design cannot attribute it confidently, and a strong experimental contrast can still lack personal importance.

Decide the next evidence step for Noor

The reviewer examines whether the same downward departure occurs at planned changes in other tiers, whether baseline trend threatens prediction, and whether the outcome is meaningful to Noor. The responsible clinician and methodologist choose any added observation, replication, design change, or claim revision. The choice protects needed care, uses prospectively stated rules where possible, and preserves the original graph and decision history.

Protect Noor's access and participation

Keep Noor's augmentative and alternative communication, interpreters, mobility, food, water, bathroom use, prescribed care, health support, rest, relationships, and emergency help available throughout the school task-completion study. Use accessible consent and assent processes when applicable and respond to withdrawal, dissent, or distress. A replication plan never supplies authority to withhold a necessary support or delay urgent action.

Apply current sources to Noor's review

Noor's source trail supports simultaneous review of overlap, trend, level, variability, immediacy, and replication. The BACB ethics hub and CASP public summary provide professional context, while the BCBA Test Content Outline identifies examination content on measurement and single-case design. The WWC Version 5.0 handbook supplies a current research-review framework. A single-case design review, systematic visual-analysis protocols, current analytic reflections, nonconcurrent multiple-baseline methods research, and a visual-analysis software tutorial describe methods and limits. ASHA supports continuous AAC access.

Rehearse Noor's review process

Before live use, run the overlap-and-trend comparison on fictional graphs with a strong effect, weak effect, delayed effect, opposite trend, carryover, missing agreement, one contradictory tier, and no replication. Confirm that reviewers preserve raw values, count planned opportunities separately from observed demonstrations, identify holds, and keep client relevance distinct from causal inference. Store test cases, expected decisions, software version, and correction log.

Close Noor's claim review

Review the overlap-and-trend comparison with Noor, the responsible clinician, and a methodologist familiar with the exact design. Preserve raw data, graph, design protocol, basic effects, demonstrations, fidelity, measurement checks, contextual events, client input, reviewer disagreements, source standard, final wording, and limits. Keep the page draft and noindex until all manifest-named reviews are complete.

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