Randomising by text message (Simple+)

If your trial is enabled for randomisation by text message (SMS), you can send a text and receive back a treatment allocation.

Text message delivery can be delayed due to network and third party issues outside the control of Sealed Envelope. We do not recommend you rely on text messaging if your randomisation is very time sensitive.


Text messaging is only available with the Simple + service - see pricing for details. Standard network text message costs also apply.

How do I randomise by text message?

Once your trial has been activated for text message randomisation, you can view instructions for randomising by text message. The details vary somewhat by trial but in general you send a specially formatted text message to the Sealed Envelope text service:

mytrial randomise patient id [strata]

mytrial is the SMS ID of your trial, patient id is the unique identifier(s) for the patient you wish to randomise, and [strata] are the stratification values if your trial is using a stratified list. You must put the word randomise or rnd between your trial name and patient identifier.

By default, the patient identifier can be anything you want, such as trial ID number, initials and date of birth, clinic number etc. Optionally, you can ask Sealed Envelope to restrict the patient identifier to conform to a certain pattern, e.g. two letters and three digits.


mytrial randomise JD 15/10/1954

Here the patient identifier is JD 15/10/1954 which is the patient's initials and date of birth.

mytrial randomise 1267821 male <40

In this example the patient identifier is 1267821 and there are two strata: gender and age-group. The patient being randomised is male and under 40 years of age.

Can I try this out?

Yes - we have a demo set up for you to try. Go to the demo text trial, log into the administration area (using the password this is a demo) and view the instructions for randomising by text message .

What about inclusion and exclusion criteria?

If your trial has inclusion and exclusion criteria enabled, it is implied by sending a text that the patient meets these criteria. Do not send a text for patients that are not eligible.

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