Monthly option expiration dates 2014

Our modeling data structure had one observation per patient per hour, until a length of stay of 15 days was reached and thus allowed us to obtain hourly probability estimates but has some limitations.

The resultant dataset can potentially repeat the same vital sign or lab values from one to three days, or until new measurements are taken.

A given value for a patient-hour may, therefore, refer to a measurement taken 72 h earlier. Information about any but the final measurement taken in a given hour is lost, so frequency of measurement cannot be analyzed.

Similarly, the possible significance of gaps between measurements is not captured in this structure, and cannot be utilized in modeling.