1. Survey Documentation and Analysis (SDA)
Tools We Use:
Survey Documentation and Analysis (SDA)
Jon Stiles, UC DATA
May 3, 2012

2. Part I. The Basics of SDA
What is SDA?
What data is available in SDA?
What can you do with SDA?
The parts of the SDA interface
Menu
Variable List
Active variables
Analysis Specification

3. Part II. Working with SDA
1. Finding data/variables/subjects
- search
- documentation
2. Analysis -
Components - rows, columns, selection, controls
Procedures - crosstabs, means, correlations
Aids in Analysis
Recoding
Saving new variables
Downloading

4. Part I. The Basics of SDA What is SDA?
SDA (Survey Documentation and Analysis) is a set of programs for the documentation and Web-based analysis of survey data.
It was developed and is maintained by the Computer-assisted Survey Methods Program (CSM) at UC Berkeley.
It was developed as a companion program with CASES (Computer Assisted Survey Execution Program), a package for collecting survey data based on structured questionnaires, using a variety of modes of data collection.
It operates on a transposed file structure, which makes analysis of datasets, especially large datasets, extremely fast.

5. Part I. The Basics of SDA What data is available in SDA? LOTS!
Many popular social science datasets (e.g. the GSS, the ANES, the PUMS from the Decennial Census, the ACS, the CPS Annual Demographic Files,…… can be found in SDA format.
Many archives (ICPSR, IPUMS, CPANDA, Roper, SDA, UCDATA, ISSR) provide access to at least some of their holdings via SDA.
ICPSR: 778 studies out of 8283, 108 out of 457 studies added this year
IPUMS: Decennial/ACS, CPS, NAPP

6. 575 Studies at ICPSR (http://www.icpsr.umich.edu/access/sda.html)

7. A brief aside: search filtering ICPSR

13. Multiple Census Samples at IPUMS (http://usa.ipums.org/usa/sda/)

14. And CPS (March files) data, as well (http://cps.ipums.org/cps/sda/)

15. Orange County Polls (UCI) (http://data.lib.uci.edu/)

17. Part I. The Basics of SDA What can you do with SDA?
SDA can be used to:
learn about a dataset (metadata, paradata)
search for variables of interest
investigate sample sizes and variable distributions
perform statistical analyses
transform, manipulate and create variables for each unit
extract and download subsets or full datasets

19. Part I. The Basics of SDA The parts of the SDA interface Menu
Variable List
Active variables
Analysis Specification

20. Basic Menu Analysis – choose
Getting Started – note that you can resize /rearrange

22. Collapsed Variable Tree

23. Active Variables

24. Analysis Specification

25. Part II. Working with SDA
1. Finding data/variables/subjects
- search
- documentation
The Codebook Menu

26. Part II. Working with SDA
1. Finding data/variables/subjects
- search
- documentation
The Search Menu

27. Part II. Working with SDA
Analysis -
Components - rows, columns, selection, controls
Procedures - crosstabs, means, correlations
Screens will vary depending upon what procedure you are using.
Start with exploratory – frequencies, cross-tabulations

28. Part II. Working with SDA
Aids in Analysis
Recoding
Saving new variables
Downloading

29. Recoding variables – on the fly
age (5-18)
age (r: 5-18)
age (d: 5-18)
age (c:13,5)
Can be used in row, column, control (Crosstabs)
Recoding variables
– Web interface

30. Creating new variables
– Web interface

31. Part II. Working with SDA
Aids in Analysis
Recoding
Saving new variables
Downloading

32. SDA Projects Under Development
What Next?
SDA Projects Under Development
Complex Standard Errors The calculation of standard errors for percentages and means in complex samples has been revised to incorporate new developments for subpopulations and for differences. Complex standard errors for regression coefficients will also be implemented.
Charts Charts were added to the MEANS program in version 3.4. Charts will also be added to the regression program in a future version.
Data Documentation Initiative (DDI) Many organizations are working together to arrive at a common standard for documenting data files using XML. CSM is participating in this ongoing effort and has been involved in developing tools to read and write DDI metadata files.