One aspect of this about unique identifiers is when users want to do double entry.
The only double entry option in this situation is to enter the data twice and then compare afterwards, since the "immediate comparison" double entry mode is not available for combined field unique entries unless the records are entered in EXACTLY the same sequence as the first time. The problem for the user is, that the system is NOT giving correct warnings in the immediate double entry if the unique index is created in contrast to entered directly.
I would like the identifier to be automatically created in the .rec file after entering 4 variables and as an aggregation of these 4 variables. For instance my identifier is ID=region number+village number+household number+member in the household number
regards Jens Lauritsen EpiData Association