Generating Indicator Variables using age ranges

[bgosiker]

Hi Everyone, 

I have a long dataset (multiple rows per person), and each row has a "start age" and "end age" to indicate the 0.5 year age range that the row is meant to represent. Ie someone would have age_start=20 and age_end=20.5. My LOWEST age_start is 17.5 and my highest age_end is 93, so there is at least one person for each 0.5 year increment between 17.5 and 93. 

I am wanting to generate time indicators based on these age ranges so that I can align everyone on the basis of age. Some people have gaps in visit (note, ID=2 is missing visit=3, so there is a gap!). Basically starting with age_start=17.5 I would want some indicator variable (let's say age_X) to be age_X=0 and then increase by 1 for each progressive 0.5 years (ie for age_start=18 age_0=0 and age_1=1). So each row should only have ONE age_x variable that is 1 and all the others would be 0. There should be 151 indicator variables generated from this for each 0.5 year range between 17.5 and 93. 

I think an array would be the best approach here, but was unsure how to get it to be based specifically on the age_start variable since each person can start at a different age and there can be gaps. Any help is appreciated!  

An example of the data I have is below: 

Data have;
 input ID  visit age_start age_end ;
datalines;1  1  17.5  18
1  2  18  18.5
1  3  18.5  19
2  1  25  25.5
2  2  25.5 26
2  4  26.5  27
3  1  51.5  52
3  2  52  52.5
3  3  52.5  53;
run;

Data I WANT:

id     visit    age_start    age_end    age0    age1      age2.....  age15  age16   age17    age18......age68    age69    ag70.......

1    1     17.5     18       1      0      0      0      0      0      0      0      0      0

1       2     18       18.5     0      1      0      0      0      0      0      0      0      0

1    3     18.5     19       0      0      1      0      0      0      0      0      0      0

2    1     25       25.5     0      0      0      1      0      0      0      0      0      0

2    2     25.5     26       0      0      0      0      1      0      0      0      0      0

2    4     26.5     27       0      0      0      0      0      0      1      0      0      0

3    1     51.5     52       0      0      0      0      0      0      0      1      0      0

3    2     52       52.5     0      0      0      0      0      0      0      0      1      0

3    3     52.5     53       0      0      0      0      0      0      0      0      0      1

[arthurcavila]

My first question would be why do you need those dummy variables? Procedures with a CLASS statement will generate the dummies you need internally.

Data have;
 input ID  visit age_start age_end ;
 array age{151} age1-age151;
 do i = 1 to 151;
 	if i = (age_start-17)*2 then age{i} = 1;
 	else age{i} = 0;
 end;
 drop i;
datalines;
1  1  17.5  18
1  2  18  18.5
1  3  18.5  19
2  1  25  25.5
2  2  25.5 26
2  4  26.5  27
3  1  51.5  52
3  2  52  52.5
3  3  52.5  53
;
run;

[bgosiker]

I was needing to export my data to run analyses in Stata so thought I needed to generate the indicator variables for it. I tried running the code you gave and ran into an issue where the data step wasn't finishing and eventually had to break it. 

[SASKiwi]

@bgosiker - the program as posted by @arthurcavila works fine for me. You have obviously changed it so post the code you are trying to run.

[bgosiker]

Dumb mistake - left off the run when I copied over!

[PaigeMiller]

Doesn't STATA generate indicator variables when you try to fit a model? Doesn't SAS give the ability to run the same models?

[bgosiker]

I wasn't sure if stata did and I'll be switching from a PC (with SAS) to a mac (with stata) in the coming days and wanted to make sure I was prepared if it didn't. If it does then that is great!