HI, Is lag and lead something that can help you ? DATA shipments2; SET shipments; IF eof1=0 THEN DO; SET shipments(firstobs=4 KEEP=Shipment_Month Shipment_Count RENAME=(Shipment_Month=lead_Shipment_Month Shipment_Count=lead_Shipment_Count)) end=eof1; END; ELSE DO; lead_Shipment_Month=.; lead_Shipment_Count=.; END; lag_Shipment_Month=lag4(Shipment_Month); lag_Shipment_Count=lag4(Shipment_Count); RUN;
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