A single-case randomization protocol deviation should be handled by protecting the participant first and preserving the evidence. Record the assigned schedule, delivered schedule, timing, reason, who decided, outcomes visible at the time, and immediate safety or access actions. Do not backfill the assignment record. A qualified methodologist should determine whether the planned test remains valid and which confirmatory, sensitivity, or descriptive analyses can be reported.

Act for welfare and required care

Use emergency, medical, consent, assent, and safety procedures without waiting for research approval. The protocol cannot delay necessary action.

Preserve two schedules

Keep assigned and delivered conditions or change points in separate fields with timestamps, reasons, and decision owners.

Classify the deviation

Record missed outcome, delayed start, early start, wrong condition, crossover, withdrawal, or another defined state and its duration.

Hold confirmatory interpretation

Route the exact facts to the named clinician, investigator, statistician, ethics, and regulatory roles before claiming the planned inference.

Report every analysis role

Label planned, modified, sensitivity, and descriptive results and explain which assignment and data each uses.

Build Wren's assigned-versus-delivered schedule log

For the single-case randomization protocol deviation question, start with a locked protocol and a versioned assigned-versus-delivered schedule log. Record Wren's design, setting, randomization unit, complete schedules, constraints, assignment probabilities, draw, selected schedule, delivered schedule, statistic, tail, tie and missing-data rules, software, and reviewers. Link each schedule position to the original time-series record. The file should let an independent analyst reconstruct post-assignment protocol deviation without guessing what was possible before outcomes.

Work the schedule example for Wren

Wren is assigned to begin intervention at observation 7. A medical absence prevents observations 7 and 8, and delivery begins at observation 9. The record retains assigned start 7 and delivered start 9. The team does not replace 7 with 9 in the randomization file or pretend that 9 was drawn. Show the schedule generator, inclusion tests, probability calculation, draw evidence, and selected sequence at full precision. This fictional example illustrates a delayed intervention start after random assignment; it does not establish a universal phase length, alpha, power level, or treatment plan.

Audit Wren's assignment evidence

Wren's log records the dated assignment, absence, missing observations, delivered start, safety and access decisions, people involved, data visible, protocol clause, and analysis hold. The original schedule and all source files remain immutable. The audit also checks timestamps, protocol amendments, allocation concealment when applicable, cancellations, replacements, missing positions, phase labels, probability totals, software version, and whether the analysis generator matches the design generator. Unresolved discrepancies stay on hold.

Prevent the assignment error in Wren's review

Forcing treatment or measurement on the assigned date to protect a p value can harm the participant. Rewriting the selected date can fabricate adherence. Wren's workflow prioritizes health and makes the methods consequence transparent. Randomization means chance operated at the named assignment step under the documented scheme. Varied, alternating, staggered, or response-guided schedules are not automatically randomized.

Integrate design and visual evidence for Wren

The methods reviewer evaluates the deviation under the exact design and missing-data structure. The report distinguishes the prospectively planned analysis, any justified sensitivity analysis, and descriptive evidence without selecting the most favorable result. The WWC Version 5.0 handbook is a research-review standard, not a universal clinical protocol. Review the graph, level, trend, variability, immediacy, overlap, consistency, measurement quality, assignment fidelity, original-unit magnitude, and every planned replication.

Protect Wren's participation

The post-assignment protocol deviation never outranks Wren's welfare. Keep augmentative and alternative communication, interpreters, mobility, food, water, bathroom use, prescribed care, health support, rest, relationships, and emergency help available. Use accessible consent and assent processes and honor withdrawal or distress. If safety, medical need, access, or choice changes the schedule, qualified people act and document the design consequence.

Use design-specific sources for Wren

For Wren's a delayed intervention start after random assignment, the BACB ethics hub and CASP public summary provide professional context, and the BCBA Test Content Outline identifies examination content on measurement and single-case design. A randomized SCED overview covers phase and alternation schemes. Research on multiple-baseline power, rapid alternation, and changing-criterion randomization shows design-specific behavior. A health-sciences methods paper discusses randomized phase, alternation, and case-placement options. Nonconcurrent multiple-baseline research addresses assignment and design-quality issues. ASHA supports continuous AAC access.

Rehearse Wren's schedule before collecting outcomes

Before the school mobility-support study begins, Wren's team runs the assigned-versus-delivered schedule log with fictional schedules and outcomes. The rehearsal checks the earliest and latest permissible assignment, probability totals, selected-schedule trace, delivered-schedule fields, statistic, missing-data behavior, and a hand-worked reference result. Reviewers store test cases, expected outputs, code version, and correction log. The dry run can repair mechanics before outcomes; it cannot use Wren's future data to change the assignment scheme.

Define Wren's stop, pause, and amendment rules

Wren's protocol names who may stop or pause the post-assignment protocol deviation, which health, safety, assent, access, staffing, technology, or feasibility events trigger action, and how urgent care proceeds. It separates an immediate protective action from a later research amendment. Any amendment receives a new version, date, rationale, approval path, and prospective assignment set; the original schedule and data remain intact. The team also tells Wren how to withdraw or raise a concern through an accessible route. These rules make the humane response predictable and keep a necessary change from being hidden as ordinary schedule variation.

Close Wren's design review

Review the assigned-versus-delivered schedule log with Wren, the responsible clinician, and a statistician or methodologist familiar with the exact design. Preserve protocol, schedule set, probabilities, draw, selected and delivered sequence, raw data, graph, code, outputs, deviations, inference limits, client input, and decisions. Keep the page draft and noindex until every named review is complete.

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