Person-years form a start to an end date

[NewUsrStat]

Hi guys, 

how can I calculate person-years from two dates for ex: 16FEB2019 and 08JAN2020? 

I have two variables with around 20.000 rows in my table. 

Thank you in advance. 

Best

[PaigeMiller]

Please tell us the desired outcome for the case where the two variables have values 16FEB2019 and 08JAN2020

[NewUsrStat]

So I have to calculate the contribution (person years) of each patient to the study from 16FEB2019 when it was included, to 08JAN2020 the last date we have.

[PaigeMiller]

This gives the same information as before. This doesn't answer the question. How many person-years is that?

[Patrick · Accepted solution]

@NewUsrStat

Based on your very lean description the two variables with dates you want to compare are in the same row. And what is a person-year? Below assumes it's just a count of calendar years.

data demo;
  dt1='16FEB2019'd;
  dt2='08JAN2020'd;
  format dt1 dt2 date9.;

  n_calendar_years=intck('year',dt1,dt2)+1;
run;
proc print data=demo;
run;
 

What could really help to explain things and remove ambiguity is if you provide some representative sample data and show us the desired result. 

[NewUsrStat]

Thank you very much Patrick for your help!

[Tom]

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@NewUsrStat wrote:

Hi guys, 

how can I calculate person-years from two dates for ex: 16FEB2019 and 08JAN2020? 

I have two variables with around 20.000 rows in my table. 

Thank you in advance. 

Best

---

You left out most (if not all) of the necessary information.

You probably have some data in addition to those two dates.  What does the data look like?  Show a small example (2 or three persons) and what result you want for that example data.

 Will you have other date ranges you want to summarize? Where will the two dates needed to define those ranges coming from? 

[NewUsrStat]

Sorry, I know there are no details but it is also not clear to me what others asked. I will ask soon.

[Quentin]

proc sql ;
select sum(date2-date1)/365.25
from have
;
quit ;