[EpiData-list] verification question
 I would like to MATCH RECORDS by more than ONE FIELD when preparing double entry verification - is this possible ?  Once a file is verified, does the corrected data reside in the *.REC or the *_dbl.REC file ?
EpiData has two principles of validation: A. Compare two separate files entered independently. B. Compare at field level while entering data.
Preparation of the two are both at the tool menu. A. Copy structure (of existing rec + chk file) B. Prepare Double Entry Verification
Actual validation: A. Is done after all data have been entered. In the document menu you can "Validate Duplicate Files". When you specify the two files up to three fields can be used to match the two files. B. Is done while entering data the second time. You can only match on one field. The corrected data resides in the ..._dbl.rec file, which is the one you are adding data to.
After point B you can run the two files with option A and get a record of how much was corrected while entering data the second time in ..._dbl.rec file.
If you want to create a unique match while entering data on more than one field a typical way of doing so would be to create a key field like this:
To do so, e.g. your matching fields are v1 v2 v3 in the check file:
v1 mustenter end v2 mustenter end v3 mustenter after entry keyfield = string(v1)+" "+string(v2)+" "+string(v3) end
keyfield noenter key unique end
I am not sure how double entry would handle this, but make a test and see how it works.
regards Jens Lauritsen EpiData Association