Use this tool to create a blocked randomisation list for your trial. The generated lists are suitable for use with our simple randomisation service. Unsure about block sizes? Use our simulation tool to help you decide.
This tool has been superseded and is only provided to allow you to reproduce lists created before March 2015. Please use the latest version for creating new lists.
Sealed Envelope Ltd. 2019. Create a blocked randomisation list. [Online] Available from: https://www.sealedenvelope.com/simple-randomiser/v1/lists/1 [Accessed 26 May 2020].
A comma separated list of treatments. For unequal allocation duplicate the treatment name, e.g.
Group A, Group A, Group B
for a 2:1 allocation ratio.
The minimum number of rows to generate. The generated list may be slightly longer than this because of the need to fill blocks.
Important! If you are using stratification, you must make sure that the list is long enough to cover the maximum number of randomisations you expect to perform within any stratum.
The safest option is to set the list length to sample size x number of strata.
Must be formatted
name: category 1, category 2, …
For example, to stratify by age you could use
Age group: Under 30, 30 - 50, Over 50
✽ For lists created before March 2015 please use this list generator to recreate your list.