Research design
Use randomization, replications, and compute matching
Set assignment units, reproducible seeds, repeated trials, blocking, and fair compute constraints across conditions.
The basic idea
Stochastic model outputs and heterogeneous item difficulty create variance. Replication estimates that variance; random assignment prevents systematic allocation differences; blocking can improve balance; compute matching keeps a treatment from winning merely because it used more resources.
Randomize benchmark items equally across arms within category blocks, repeat each item-condition cell, and match estimated provider cost or model calls.
How to do it
- 1
Choose whether assignment occurs by item, participant, or entire run.
- 2
Save a seed and allocation rule that another analyst can reproduce.
- 3
Select repetitions based on the estimand and expected variance, not a convenient round number.
- 4
Choose whether to match calls, turns, token budgets, or estimated cost and document what remains unmatched.
What to watch for
- Repeated calls are not human participants and should not be described as such.
- Blocking variables must be measured before assignment.
- More replications can become expensive quickly, especially with option-order variants.
What a useful result looks like
These controls make treatment comparisons more stable, auditable, and resistant to accidental compute advantages.