https://communities.sas.com/t5/SAS-Programming/check-whether-any-date-ranges-for-a-patient-overlap/m-p/405569#M98685 <P>Use the lag() function to retrieve the enddate of the previous observation, and compare that with the filldate of the current obs.</P> Thu, 19 Oct 2017 14:40:24 GMT Kurt_Bremser 2017-10-19T14:40:24Z https://communities.sas.com/t5/SAS-Programming/check-whether-any-date-ranges-for-a-patient-overlap/m-p/405560#M98677 <P>I work on health care claims and right now I have a task to determine if any date ranges for a single patient overlap and I need to count the number of overlapping days for each date range for that patient. Here is the snap shot of the data. Also for the overlapping days I need to calculate the total dosage and also calculate the average dose for those overlapping days. Any help is greatly appreciated.</P><P>&nbsp;</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="overlapping date ranges" style="width: 376px;"><img src="https://communities.sas.com/t5/image/serverpage/image-id/16011i0524DFFDEB84C09A/image-size/large?v=v2&amp;px=999" role="button" title="Capture.PNG" alt="overlapping date ranges" /><span class="lia-inline-image-caption" onclick="event.preventDefault();">overlapping date ranges</span></span></P> Thu, 19 Oct 2017 14:29:30 GMT https://communities.sas.com/t5/SAS-Programming/check-whether-any-date-ranges-for-a-patient-overlap/m-p/405560#M98677 ask77 2017-10-19T14:29:30Z https://communities.sas.com/t5/SAS-Programming/check-whether-any-date-ranges-for-a-patient-overlap/m-p/405569#M98685 <P>Use the lag() function to retrieve the enddate of the previous observation, and compare that with the filldate of the current obs.</P> Thu, 19 Oct 2017 14:40:24 GMT https://communities.sas.com/t5/SAS-Programming/check-whether-any-date-ranges-for-a-patient-overlap/m-p/405569#M98685 Kurt_Bremser 2017-10-19T14:40:24Z