What is the Experiment Randomizer?
Randomize experiment run order and group assignments with this free experiment randomizer. Shuffle trial order, assign samples to treatment groups, or shuffle replicate blocks using Fisher–Yates randomization. Optional seed for reproducible lab plans. Runs in your browser.
How to use the Experiment Randomizer
- Choose Shuffle Order, Assign Groups, or Replicate Shuffle.
- Enter samples, treatments, or conditions (one per line).
- Set number of groups or replicates as needed.
- Optionally enter a seed to reproduce the same randomization later.
- Copy the run order and group assignments to your lab notebook.
Common use cases
- Randomizing treatment order in multi-condition assays
- Assigning animals or plates to control vs treatment groups
- Shuffling replicate block order for PCR or incubation runs
- Teaching experimental design and bias control
- Documenting randomization with a fixed seed in lab notebooks
Frequently asked questions
- Why randomize experiment order?
- Randomizing run order controls for time-of-day, instrument drift, and learning effects. It reduces bias when comparing treatments in lab and field experiments.
- What is a randomization seed?
- A seed makes the shuffle reproducible. The same items and seed always produce the same order — useful for documenting your randomization in lab records.
- How does group assignment work?
- Items are shuffled, then distributed round-robin across groups so sizes differ by at most one. You can name groups (e.g. Control, Treatment).
- What is replicate shuffle?
- Each condition is repeated N times, forming a pool of all runs. The pool is shuffled to give a randomized execution order across replicates.
- Is this suitable for clinical trials?
- This tool helps with basic lab randomization. Regulated clinical trials require formal randomization protocols and audit trails beyond a simple web tool.
