Question
Question Posted 02/26/25:
Dear Experts
I found there are 'VISCODE' and 'VISCODE2' for some study files (for example the DXSUM file, ADVERSE file etc). When i looked at their meaning in the data dictionary file, one is 'Visit code' the other is 'Translated visit code'. Which one should i use? I want to select the records for the baseline visit 'bl'.
Dear Experts
I found there are 'VISCODE' and 'VISCODE2' for some study files (for example the DXSUM file, ADVERSE file etc). When i looked at their meaning in the data dictionary file, one is 'Visit code' the other is 'Translated visit code'. Which one should i use? I want to select the records for the baseline visit 'bl'.
Response posted 02/26/25 by Monica E.:
The best thing to use right now is VISCODE2 which is available in most files downloaded from LONI. This translates the tracking visit code (VISCODE in most files) into the corresponding “month”. Note that VISCODE2 is not necessarily an accurate calculation of time since the baseline (or screening visit)…it just translates the tracking visit code to that year’s visit. So for example, if the tracking visit code is for the year 4 visit, VISCODE2 will be m48 even if it is closer to 54 months since baseline (or screening).
If you want actual time between visits, it is best to use EXAMDATE to calculate the actual time.
This information was originally provided by Danielle Harvey in the ADNI Google Groups page: https://groups.google.com/g/adni-data/c/_5gJm0w5BX4/m/agBcCUmoBQAJ
If you want actual time between visits, it is best to use EXAMDATE to calculate the actual time.
This information was originally provided by Danielle Harvey in the ADNI Google Groups page: https://groups.google.com/g/adni-data/c/_5gJm0w5BX4/m/agBcCUmoBQAJ
