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1. Multi-Program Capture-Recapture Simulation Using SAS Macros Shane Roberts
William Gosnell
2. Simulations in SAS Positives
Can run extremely complicated designs
Lots of people know and use SAS
Online code resources
3. Negatives
Steep learning curve
Code not as intuitive as some others
Little online help for this type of analysis
Can freeze older computers
4. Functions of Simulations Assist in experimental design
Mimic not mirror reality
Determine effects of system parameters on the outcome of interest
Extend our observations on possible relationships in the system
5. Types of Simulations Data based
Based on real data
Model based
All simulated elements are internally defined in the simulation
6. What are we doing? Simulate a closed population
Simulate sampling of that population during two years (2 groups)
Calculate and compare population estimates of each group based on capture-recapture
8. First, we need to: Simulate closed population in SAS
Simple juvenile and adult age structure
Simulate sampling of that population during two years (create two groups)
Create capture history file with two groups for input into Program MARK
9. Next, we need to: Run 2-group closed population model in Program MARK to determine input file structure
10. Then we: Create header and footer for capture history file
11. Finally, we add commands to: Strip output strings of interest with GREP and save these strings to .txt files
Read these .txt files back into SAS to calculate means over multiple simulation runs
12. Where was MARKWAIT? Apparently do not need it with new version of Program MARK
13. Simulations in Program MARK?
14. Simulations in Program MARK
What bugs still exist?
Can’t simulate community and population dynamics like the multi-program simulations can
15. Useful Resources Dr. Jim Peterson
Georgia Co-op Webpage
http://coopunit.forestry.uga.edu/unit_homepage
Dr. Gary White’s Webpage
http://www.warnercnr.colostate.edu/~gwhite/mark/mark.htm
“Program MARK: A Gentle Introduction…”
http://www.phidot.org/software/mark/docs/book/
SAS Online Documentation
http://v8doc.sas.com/sashtml/
16. Questions?