Random select, do a calculation, then repeat

[mandyosu01]

Hello SAS users,

Thank you so much in advance for reading the question. 

I have the following sample data and code. These are the data steps I needed:

1. From the first firm, Firm 1, randomly match with another firm, by Group

2. Create a new variable, Year 2 Profit. Use the matched firm's Rate as a growth rate to multiply Firm 1's Year 1 Profit to calculate Firm 1 's Year 2 Profit. Year 2 Profit= Rate * Year 1 Profit 

3. Use the new variable, Year 2 Profit, to rematch with a random firm, by Group.

4. Create a new variable, Year 3 Profit. Use the newly matched firm's Rate as a growth rate to multiply Year 2 Profit. Year 3 Profit = Rate * Year 2 Profit 

What I look for:

Get all Year 4,5,6,7 Year Profit... for Firm 1.

Get all Year 2,3,4,5,6,7 Year Profit... for all other firms.

Some firms have more than 7 years of data, and some firms have less than 7 years of data. so some may have Year 8 Profit, Year 9 Profit...

Firm	Year	Rate	Group	Year 1 Profit	Year 2 Profit	Year 3 Profit	Year 4 Profit	Year 5 Profit	Year 6 Profit	Year 7 Profit
A	2010	0.1	1	100
A	2001	0.15	2	90
B	1998	0.01	1	101
B	1995	0.2	1	95
B	1991	0.02	2	98
C	2010	0.3	2	103
C	2020	0.05	2	110
C	2009	0.1	3	90

I have the select code, but dont know how to repeat the process.

proc surveyselect data=have  sampsize=1 out=mySamples;
strata group;
run;

Data a1, set mySamples;

Year 2 Profit  = Year 1 Profit * Rate;

Run;

proc surveyselect data=a1  sampsize=1 out=mySamples2;
strata group;
run;

Data a2, set mySamples2;

Year 3 Profit  = Year 2 Profit * Rate;

Run;

Thank you so much in advance!

[data_null__]

Use REPS= on the PROC statement.

[mandyosu01]

Thanks. I dont think the repts = works here since I have a calculation between each random draw. 

[Reeza]

If you have a program that works, see the below tutorial on converting it to a macro. 
But know that I do agree with @data_null__ suggestion of adding REPS and then using BY group processing instead. It's hard to follow exactly what's going on, I don't see how you're matching anything for example. 

Tutorial on converting a working program to a macro

This method is pretty robust and helps prevent errors and makes it much easier to debug your code. Obviously biased, because I wrote it 🙂 https://github.com/statgeek/SAS-Tutorials/blob/master/Turning%20a%20program%20into%20a%20macro.md

Examples of common macro usage

https://communities.sas.com/t5/SAS-Communities-Library/SAS-9-4-Macro-Language-Reference-Has-a-New-Ap...

[mandyosu01]

Thank you for the information. I will look into it. I am matching firms by group. As long as they are in the same group, they could be matched. Can you help me with the Macro since I am very new to Macro. Thanks.