I have another huge problem with my observation data: Due to 'real life' observation restrictions, we had to code every action of the oberved person. Each action was described by a number of variables and the start and end time/duration. So the data looks like this. Nr start time end time action-type var 1 var2... ...varn obsDay 1 8:00:00 8:00:20 70 100 200 ....450 1 2 8:00:10 8:00:40 85 103 205 ...460 1 ... x 16:00:00 16:03:30 70 100 0 ...450 z As you can see, some of the actions are overlapping due to 'multi tasking', so they use the same time, at least partially; and each action has a different length. Now I would like to reorganize the data to a time based matrix with equal steps; each case should represent a 5 sec. step (the smallest possible length). If there are two (or y) cases taking up the same time, the action type and var codes should be added as AT 2, var 2-1, var 2-2 to var 2-n or AT y, var y-1, var y-2, var y-n. (The number of the multiple tasks is in no case higher than 4 - no individual was able to do more than 4 things at once...;-) - so y<=4) So the output data should look like this. Nr start time action-type var 1 var2... ...varn AT2 var2-1 var2-2 var2-n 1 8:00:00 70 100 200 450 0 0 0 ...0 2 8:00:05 70 100 200 450 0 0 0 ...0 3 8:00:10 70 100 200 450 85 103 205 ...460 4 8:00:15 70 100 200 450 85 103 205 ...460 5 8:00:20 85 103 205 460 0 0 0 ...0 6 8:00:25 85 103 205 460 0 0 0 ...0 7 8:00:30 85 103 205 460 0 0 0 ...0 8 8:00:30 85 103 205 460 0 0 0 ...0 ... x16:03:25 70 100 0 450 0 0 0 ...0 *(A) By Ray to SPSSX-L on 2002/07/21. DATA LIST LIST /Nr(F8) stime etime(2TIME8) atype var1 var2 var3 var4 day(6F8.0). BEGIN DATA. 1 8:00:00 8:00:20 70 100 200 250 450 1 2 8:00:10 8:00:40 85 103 205 230 460 1 3 8:00:15 8:00:45 90 110 200 200 400 1 4 16:00:00 16:03:30 70 100 0 200 450 10 5 16:01:25 16:02:05 75 100 0 200 450 10 END DATA. LIST. COMPUTE #s=stime. * Next line assumes the maximum duration of an activity is 24 hours. * 24*60*60/5=17280. LOOP cnt=1 TO 17280. COMPUTE stime=#s. XSAVE OUTFILE='c:\\temp\\data1.sav' KEEP=stime atype var1 TO var4 . COMPUTE #s=#s + 5. END LOOP IF stime>=etime. EXECUTE. GET FILE='c:\\temp\\data1.sav'. SORT CASES BY stime atype. COMPUTE casen=$CASENUM. RANK VARIABLES=casen BY stime /RANK INTO idx. VECTOR at(4F8) /var1_(4F8) /var2_(4F8) /var3_(4F8) /var4_(4F8). COMPUTE at(idx)=atype. DO IF idx=1. + COMPUTE var1_1=var1. + COMPUTE var1_2=var2. + COMPUTE var1_3=var3. + COMPUTE var1_4=var4. ELSE IF idx=2. + COMPUTE var2_1=var1. + COMPUTE var2_2=var2. + COMPUTE var2_3=var3. + COMPUTE var2_4=var4. ELSE IF idx=3. + COMPUTE var3_1=var1. + COMPUTE var3_2=var2. + COMPUTE var3_3=var3. + COMPUTE var3_4=var4. ELSE IF idx=4. + COMPUTE var4_1=var1. + COMPUTE var4_2=var2. + COMPUTE var4_3=var3. + COMPUTE var4_4=var4. END IF. AGGREGATE /OUTFILE=* /BREAK=stime /at1 TO at4 = FIRST(at1 TO at4) /var1_1 TO var1_4 = FIRST(var1_1 TO var1_4) /var2_1 TO var2_4 = FIRST(var2_1 TO var2_4) /var3_1 TO var3_4 = FIRST(var3_1 TO var3_4) /var4_1 TO var4_4 = FIRST(var4_1 TO var4_4). COMPUTE nr=$CASENUM. ADD FILES FILE=* /KEEP=nr stime at1 var1_1 TO var1_4 at2 var2_1 TO var2_4 at1 var3_1 TO var3_4 at1 var4_1 TO var4_4.