According to the Mimic III documentation:

All dates in the database have been shifted to protect patient confidentiality. Dates will be internally consistent for the same patient, but randomly distributed in the future. Dates of birth which occur in the present time are not true dates of birth. Furthermore, dates of birth which occur before the year 1900 occur if the patient is older than 89. In these cases, the patient’s age at their first admission has been fixed to 300.

My question is whether the month/day/time information has been obfuscated as well... ie if the subject's ADMITTIME is stored as 4/11/2172 19:40 - can I reliably say that the actual patient was admitted on April 11th in "some year" or has all of that information been shifted as well?

  • 2
    Since the documentation says the dates are "randomly distributed" in the future, it would seem that the months are probably NOT accurate, thus limiting a seasonal analysis. Commented Apr 6, 2017 at 12:56
  • 2
    See here: seasonality is somewhat preserved: opendata.stackexchange.com/questions/7550/… Commented Apr 6, 2017 at 13:11

1 Answer 1


The answer is No - you can't extract accurate month, day or year data from MIMIC.

De-identification diagram: enter image description here

The de-identification example actually shows that the month, day and year are all shifted.

As @Gary Weissman pointed out in the question comments, the days of the week and "approximate" seasonality are preserved in MIMIC II, and MIMIC III follows the same de-identification process.

1.4.4 De-identification of patients’ data [...]

• The day of the week and season of the year were preserved.

The complete information can be found here

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.