Completely new to this so very thankful for your help. In a crossover study with Treatments X, Y, and Z (order is randomly assigned), under each treatment there are repetitive measurements at 3 different time points (Time 1, 2, and 3). I need to find the difference of time 2 and 1 under treatments X and Y and then the difference between those two values. So something to the effect of (Y2-Y1) - (X2-X1). I used wide data format and my codes work but they are highly repetitive because X/Y occur randomly in each treatment period: if treatment_1 = "X" then difference_X = treatment1_time2 - treatment1_time1; if treatment_2 = "X" then difference_X = treatment2_time2 - treatment2_time1; if treatment_3 = "X" then difference_X = treatment3_time2 - treatment3_time1; if treatment_1 = "Y" then difference_Y = treatment1_time2 - treatment1_time1; if treatment_2 = "Y" then difference_Y = treatment2_time2 - treatment2_time1; if treatment_3 = "Y" then difference_Y = treatment3_time2 - treatment3_time1; and then I subtracted difference_X from difference_Y. I tried using array and do loops but since treatment X can occur in treatment periods 1, 2, or 3, I couldn't make it work with fewer lines of codes. Would something like this be more efficiently accomplished using the long format? Or is there a data formatting/cleaning function that I need to learn?
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