Hi, I am new to SAS and I was hoping I could get some help in this forum. I would like to know how I can calculate the depreciated/appreciated value based on the value avaiable within each group. So if I have the following table, data test; input id km sale dep_rate; datalines; 1 10000 0 -0.05 1 20000 0 -0.05 1 30000 200 -0.05 1 40000 0 -0.05 1 50000 0 -0.05 1 60000 0 -0.05 2 10000 0 -0.02 2 20000 0 -0.02 2 30000 500 -0.02 2 40000 0 -0.02 2 50000 0 -0.02 2 60000 0 -0.02 3 10000 0 -0.03 3 20000 0 -0.03 3 30000 300 -0.03 3 40000 0 -0.03 3 50000 0 -0.03 ; run; I would like to know how to achive the following result. It calculates the depreciated/appreicated value of each group based on it's depreciation rate and each km group. ID KM SALE DEP_RATE OUTCOME 1 10000 0 -0.05 220.50 1 20000 0 -0.05 210.00 1 30000 200 -0.05 200.00 1 40000 0 -0.05 190.00 1 50000 0 -0.05 180.50 1 60000 0 -0.05 171.48 2 10000 0 -0.02 520.20 2 20000 0 -0.02 510.00 2 30000 500 -0.02 500.00 2 40000 0 -0.02 490.00 2 50000 0 -0.02 480.20 2 60000 0 -0.02 470.60 3 10000 0 -0.03 318.27 3 20000 0 -0.03 309.00 3 30000 300 -0.03 300.00 3 40000 0 -0.03 291.00 3 50000 0 -0.03 282.27 I have a feeling that I need to use retain, loop and lag to find depreciated value first, then sort the other way around to find appreciated value. Finally use the value from depreicated or appreciated variable as RESULT. However, I can not figure out how I should utilise those functions to achive my result..... Any advice would be much appreciated. Tom
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