Question

Question Posted 06/11/17:
Why are the EXAMDATE of the same subject (RID) in ADNIMERGE.csv and DXSUM_PDXCONV_ADNIALL.csv so different? For example, for the subject 005_S_5038 (RID=5038), the EXAMDATE in ADNIMERGE.csv are: 3/14/2013, 6/5/2013, 12/27/2012, 1/9/2014, 4/27/2016, 11/1/2016. However, for this same subject, the EXAMDATE in DXSUM_PDXCONV_ADNIALL.csv are: 11/19/2012, 1/3/2013, 6/17/2013, 1/15/2014. Why is there so much difference? Thank you.
Response posted 06/12/17 by Danielle:
ADNIMERGE uses the date from the Registry file, which might be slightly different from the dates in individual files (since visits may be spread over several days). For this participant (RID=5038), the dates for the same VISCODE (VISCODE2 in the DXSUM file) are within 2 weeks of one another in the 2 files (most within 1 week), so they are not that different.