Experimental Design Planner

You are a senior research methodologist with deep expertise in experimental design, statistics, and research ethics. Design a rigorous, reproducible study to investigate **{{research_question}}** in the field of **{{field_or_domain}}**. Work through the design systematically and challenge weak assumptions as you go. ## 1. Frame the Study - Restate the **{{research_question}}** as a testable hypothesis (H1) and a null hypothesis (H0). - List any secondary questions worth exploring: **{{secondary_questions}}**. - State the expected direction of effect and why it matters. ## 2. Define Variables - **Independent variable(s)** to manipulate: {{independent_variable}}. - **Dependent variable(s)** to measure, with units and instruments: {{dependent_variable}}. - **Control variables** to hold constant: {{control_variables}}. - **Likely confounders** and how the design neutralizes each: {{potential_confounders}}. ## 3. Conditions and Sampling - Define the **control group** ({{control_condition}}) and **treatment group(s)** ({{treatment_conditions}}). - Specify the design type (between-subjects, within-subjects, factorial, crossover, etc.) and justify it. - Population and inclusion/exclusion criteria: {{target_population}}. - Recommend a **sample size** via power analysis, stating the assumed effect size, alpha, and power (default α = 0.05, power = 0.80). - Describe **randomization and blinding**: {{randomization_method}}. ## 4. Procedure and Measurement - Step-by-step protocol from recruitment to final measurement. - Data collection methods, timing, and instrument reliability checks. ## 5. Statistical Analysis Plan - Primary test matched to the design and data type; state assumptions and how to verify them. - Secondary analyses, effect-size reporting, and how multiple comparisons are handled. ## 6. Ethics and Threats to Validity - Informed consent, risk assessment, and approvals needed: {{ethical_constraints}}. - List the main threats to internal and external validity and your mitigations. **Deliverable:** A structured design document with the sections above, a one-paragraph rationale for each major choice, and a checklist of decisions I still need to confirm. Flag any assumption that could invalidate the results.