By name: clinical-trial description: Designs and analyzes clinical trials including sample size calculation, randomization schemes, endpoint selection, CONSORT reporting, and interim analysis planning; trigger when users ask about RCTs, Phase I-IV trials, or clinical study design.
When to Trigger
Activate this skill when the user mentions:
- Clinical trial design, RCT, randomized controlled trial
- Sample size calculation, power analysis for trials
- CONSORT, STROBE, SPIRIT guidelines
- Phase I, II, III, IV trials
- Primary/secondary endpoints, composite endpoints
- Interim analysis, adaptive trial design, futility
- Blinding, randomization, allocation concealment
- Intention-to-treat (ITT), per-protocol analysis
Step-by-Step Methodology
- Define the research question - Specify PICO (Population, Intervention, Comparator, Outcome). Determine if superiority, non-inferiority, or equivalence design is appropriate.
- Select trial phase and design - Choose phase (I: safety/dose, II: efficacy signal, III: confirmatory, IV: post-market). Consider parallel, crossover, factorial, or adaptive designs.
- Primary endpoint selection - Define primary outcome (must be clinically meaningful). Specify measurement timing and minimal clinically important difference (MCID).
- Sample size calculation - Specify alpha (typically 0.05, two-sided), power (typically 80-90%), expected effect size, and dropout rate. Use appropriate formula for the endpoint type (continuous, binary, time-to-event).
- Randomization and blinding - Recommend randomization method (simple, block, stratified, minimization). Specify blinding level (open-label, single, double, triple).
- Statistical analysis plan - Pre-specify primary analysis method (t-test, chi-square, log-rank, mixed models). Define interim analysis schedule with alpha-spending function (O'Brien-Fleming, Lan-DeMets).
- Reporting - Follow CONSORT for RCTs, STROBE for observational, SPIRIT for protocols. Include flow diagram, enrollment numbers, and all pre-specified analyses.
Key Databases and Tools
- ClinicalTrials.gov - Trial registration and results
- Cochrane Library - Systematic reviews of trials
- FDA / EMA guidance documents - Regulatory requirements
- nQuery / PASS / G*Power - Sample size software
- CONSORT / SPIRIT checklists - Reporting standards
Output Format
- Sample size as a table: assumptions, formula, per-arm and total N.
- Trial design as a structured summary: phase, design type, arms, blinding, duration.
- CONSORT flow diagram description with all participant numbers.
- Statistical analysis plan with pre-specified primary and secondary analyses.
Quality Checklist
- PICO clearly defined
- Primary endpoint is clinically meaningful and measurable
- Sample size assumptions explicitly stated with references
- Dropout rate factored into sample size
- Randomization and blinding method specified
- Multiple comparison adjustment for secondary endpoints
- Interim analysis boundaries pre-specified if applicable
- ITT and per-protocol populations defined
- Regulatory guideline alignment noted (FDA/EMA/ICH)