Exp Lens Randomization Blocking

Randomization & Blocking Experimental Design Lens

Philosophical Mode: Design-Structural Primary Question: "Where does comparability come from?" Focus: Assignment Mechanisms, Blocking Factors, Stratification, Balanced Designs, Replication

Arguments

/autoskillit:exp-lens-randomization-blocking [context_path] [experiment_plan_path]

• context_path (optional positional arg 1) — Absolute path to a lens context file containing IV/DV tables, H0/H1 hypotheses, controlled variables, and success criteria. If provided, read this file before beginning analysis to obtain structured context. If omitted, discover context by exploring the CWD.
• experiment_plan_path (optional positional arg 2) — Absolute path to the full experiment plan. If provided, read for complete experimental methodology and design. If omitted, locate the experiment plan by exploring the CWD.

When to Use

• Experiment uses randomization or structured assignment
• Need to verify blocking and stratification
• Checking for pseudoreplication
• User invokes /autoskillit:exp-lens-randomization-blocking or /autoskillit:make-experiment-diag randomization

Critical Constraints

NEVER:

• Modify any source code files
• Assume comparability without tracing its source
• Create files outside {{AUTOSKILLIT_TEMP}}/exp-lens-randomization-blocking/
• Run subagents in the background (run_in_background: true is prohibited)

ALWAYS:

• Trace the exact mechanism that creates comparability between treatment groups

• Identify every nuisance factor and how it is controlled

• Flag pseudoreplication risks (replicating at the wrong unit)

• Verify that replication is adequate for the claimed inferential precision

• BEFORE creating any diagram, LOAD the /autoskillit:mermaid skill using the Skill tool - this is MANDATORY

• If the Skill tool cannot be used (disable-model-invocation) or refuses this invocation, do NOT proceed with diagram creation. Abort this step and omit the diagram from output.

• Write output to {{AUTOSKILLIT_TEMP}}/exp-lens-randomization-blocking/exp_diag_randomization_blocking_{YYYY-MM-DD_HHMMSS}.md

• After writing the file, emit the structured output token as literal plain text with no markdown formatting on the token name (the adjudicator performs a regex match):

  diagram_path = /absolute/path/to/{{AUTOSKILLIT_TEMP}}/exp-lens-randomization-blocking/exp_diag_randomization_blocking_{...}.md
  

Analysis Workflow

Step 0: Parse optional arguments

If positional arg 1 (context_path) is provided and the file exists, read it to obtain IV/DV tables, H0/H1 hypotheses, controlled variables, and success criteria. If positional arg 2 (experiment_plan_path) is provided and exists, read the experiment plan for full methodology. Use this structured context as the foundation for Steps 1-5; skip the CWD exploration for these fields if the context file supplies them.

Step 1: Launch Parallel Exploration Subagents

Spawn Explore subagents to investigate:

Assignment Mechanism

• Find how experimental units are assigned to conditions
• Look for: random, assign, allocate, split, stratify, block, hash, bucket

Blocking & Stratification

• Find blocking factors and stratification variables
• Look for: block, strata, stratify, covariate, match, pair, group_by

Replication Structure

• Find how many independent replicates exist per condition
• Look for: replicate, repeat, trial, run, seed, fold, n_replications

Order & Timing Effects

• Find potential for carryover or order effects
• Look for: order, sequence, carryover, period, washout, crossover, time

Exclusion & Attrition

• Find how units are excluded or drop out during the experiment
• Look for: exclude, drop, attrition, missing, censor, incomplete, filter

Step 2: Map the Allocation Flow

Trace: Population → assignment → analysis. Identify randomization unit, blocking factors, replication adequacy, and potential confounds.

Step 3: CRITICAL — Analyze Comparability Source

Distinguish: True randomization / Blocked randomization / Matched pairs / Deterministic assignment

For each: Is the comparability mechanism strong enough for the claimed inference?

Step 4: Create the Diagram

Direction: TB. Subgraphs: POPULATION/POOL, BLOCKING, RANDOMIZATION, TREATMENT ARMS, ANALYSIS

Step 5: Write Output

Write the diagram to: {{AUTOSKILLIT_TEMP}}/exp-lens-randomization-blocking/exp_diag_randomization_blocking_{YYYY-MM-DD_HHMMSS}.md (relative to the current working directory)

Pre-Diagram Checklist

Before creating the diagram, verify:

• LOADED /autoskillit:mermaid skill using the Skill tool
• Using ONLY classDef styles from the mermaid skill (no invented colors)
• Diagram will include a color legend table

Related Skills

• /autoskillit:make-experiment-diag - Parent skill
• /autoskillit:mermaid - MUST BE LOADED before creating diagram
• /autoskillit:exp-lens-causal-assumptions
• /autoskillit:exp-lens-unit-interference