st: Merging 2 variables to calculate time elapse (time/date)

["Penn, Amy" <Amy.Penn@ucsf.edu>]

Dear Statalist users,

I am very much a beginner in Stata, and I have Stata 11.0.  I have read the “help dates” instructional from Stata, but am still confused.  For my project in the Zambian hospital setting, I must calculate the elapsed time in minutes of 2 sets of variables, they are:

Var1date: Date patient departed from the clinic
Var1time: Time patient departed from the clinic

Var2date: Date patient arrived at the hospital
Var2time: Time patient arrived at the hospital

The time variables have type “str5” and format “%5s.”  The date variables have the type “long” and format “%dD_m_Y.”  (I also do not quite understand the meaning of “str5,” “%5s,” and “long.”)  

I would like to calculate the time difference (in minutes) between the time the patient left the clinic to when the patient arrived at the hospital.  How would I merge, for example, Var2date and Var2time into “Var2” from which I may subtract Var1 (Var2-Var1 = time transport takes).

Thanks very much for your consideration,
Amy

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