1. Introduction to Survey Documentation and Analysis (SDA)
Jon Stiles, UC DATA
April 1, 2010

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….) provide at least some of their holdings in SDA format.

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

7. A brief aside: search filtering ICPSR

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

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

18. Cultural Policy and Arts National data Archive

19. UC DATA: California Polls

21. 6 Studies at Roper (http://www.icpsr.umich.edu/access/sda.html)

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

23. University of Maryland (PopCenter) (http://www.webuse.umd.edu/)

25. 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

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

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

30. Collapsed Variable Tree

31. Active Variables

32. Analysis Specification

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

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

35. 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

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

37. 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

38. Creating new variables
– Web interface

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

40. 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 is being revised to incorporate new developments for subpopulations and for differences. Complex standard errors for regression coefficients will also be implemented in phase 2 of this project.
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.