Unequal assignment probabilities single-case randomization requires an analysis that respects the actual probability of every schedule. Preserve the blocked, weighted, sequential, or adaptive draw mechanism and calculate each permissible assignment's probability. An unweighted count can give the wrong reference distribution. For a one-sided exact test, sum the probability mass of assignments with statistics at least as extreme as observed under the declared rule, subject to qualified methods review.
Reconstruct the actual draw mechanism
Document blocks, weights, stages, rerandomization, adaptivity, and any dependency between choices. Do not infer equal probabilities from a list of schedules.
Calculate schedule probabilities
Give each complete permissible assignment its probability or a reproducible algorithm for obtaining it. Reconcile the total probability to one.
Use a probability-respecting tail
Apply the declared extremeness rule and sum the assignment probabilities in the tail. Obtain specialist review for complex schemes.
Audit software weights
Verify that the package accepts and applies the intended probability law rather than silently enumerating schedules equally.
Report why weights existed
Explain the clinical, logistical, blocking, or design reason and the consequences for inference and attainable precision.
Build Uri's assignment-probability ledger
For the unequal assignment probabilities single-case randomization question, start with a locked protocol and a versioned assignment-probability ledger. Record Uri'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 weighted schedule randomization without guessing what was possible before outcomes.
Work the schedule example for Uri
Uri's four schedules have probabilities 0.10, 0.20, 0.30, and 0.40. The selected fourth schedule has an observed statistic. Schedules three and four are at least as extreme, so their tail probability is 0.30 + 0.40 = 0.70. Counting two of four schedules would yield 0.50 and would ignore the actual draw mechanism. Show the schedule generator, inclusion tests, probability calculation, draw evidence, and selected sequence at full precision. This fictional example illustrates a nonuniform set of schedules; it does not establish a universal phase length, alpha, power level, or treatment plan.
Audit Uri's assignment evidence
Uri's ledger reconciles all four probabilities to 1.00, stores how the weighted draw was implemented, identifies the selected schedule, lists every statistic, marks schedules three and four in the tail, and sums probability mass 0.70. A methodologist verifies the calculation and assumptions. 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 Uri's review
Software may default to equal schedule weights even when the protocol used unequal probabilities. Uri's release test compares the software distribution with the probability ledger before any result is reported. 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 Uri
The team explains why probabilities differed and whether weighting affected precision, burden, or participant access. It reports both the number of tail schedules and their probability mass so readers can see why a simple fraction is inappropriate. 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 Uri's participation
The weighted schedule randomization never outranks Uri'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 Uri
For Uri's a nonuniform set of schedules, 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 Uri's schedule before collecting outcomes
Before the telepractice parent-coaching study begins, Uri's team runs the assignment-probability ledger 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 Uri's future data to change the assignment scheme.
Define Uri's stop, pause, and amendment rules
Uri's protocol names who may stop or pause the weighted schedule randomization, 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 Uri 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 Uri's design review
Review the assignment-probability ledger with Uri, 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.
Related resources
- How to Handle a Protocol Deviation After Single-Case Random Assignment
- How to Randomly Assign Cases to Fixed Multiple-Baseline Staggers
- How to Handle Missing Outcomes in a Single-Case Randomization Test
- How to Randomize a Changing-Criterion Schedule
Sources
- Behavior Analyst Certification Board, Ethics Information and Ethics Codes
- Council of Autism Service Providers, ABA Practice Guidelines Version 3.0 public summary
- Behavior Analyst Certification Board, BCBA Test Content Outline, 6th edition
- What Works Clearinghouse Procedures and Standards Handbook, Version 5.0
- Randomized Single-Case Experimental Designs in Healthcare Research: What, Why, and How?
- Power of a Randomization Test in a Single Case Multiple Baseline AB Design
- Randomization Tests for Single Case Designs with Rapidly Alternating Conditions
- Type I Error Rates and Power of Two Randomization Test Procedures for the Changing Criterion Design
- Randomized Single-Case Intervention Designs and Analyses for Health Sciences Researchers
- Examining and Enhancing the Methodological Quality of Nonconcurrent Multiple-Baseline Designs
- American Speech-Language-Hearing Association, Augmentative and Alternative Communication