If you use a Random-Trigger with a uniform distribution and you have infinite participants the query for the trigger is very complex, because it runs through all participants.
As a consequence the installtion will be very slow, participants will be rejected from your survey and the trigger loads for ever.
Instead of using a Random-Trigger -> Work with user-defined-variables + Recoding-Trigger and Modulo(mod)
What is Modulo?
Modulo (mod) is a mathematical function that names the remainder by dividing two integers.
Example: 10 mod 3 = 1 (10:3 = 3 -> rest 1)
14 mod 5 = 4 (14:5 = 2 -> rest 4)
16 mod 3 = 1 (16:3 = 5 -> rest 1)
Solution:
Recoding-Trigger with LFDN and Mod
What is lfdn?
Every participant has a unique lfdn (participants consequente number). If you use this number with mod you create also a random trigger with a uniform distribtution.
Setup uniform distribution for numbers 1-5
- Setup User-defined-variables (Project properties -> user-defined-variables -> Number of user-defined-variables: 1)
- Jump to the page where you wanna setup your random uniform distribution
- Create Recoding Trigger (Suvey-Menu -> Questionnaire-Editor -> Page-> Trigger -> Recoding-Trigger)
Settings of the Trigger:
Open image-20210615-072929.png
Detail configuration:
Open image-20210615-073306.png
Variable to be recoded: c_000x
Value: MOD(#lfdn# , 5 ) + 1
For 6 Random-numbers use 6 instead of 5..
If you wanna see the values of the lfdn and c_000x (user-defined-variable) use the following code in the questionnaire text or where you want
