SDA: Projects

Projects

SDA Projects Under Development

Conversion to a fully Servlet-based architecture in SDA 4.0
The next major version (4.0) of SDA will convert completely from CGI to Java Servlets for the Web interface. (The current SDA interface is a blend of CGI and servlet-based components.) This will allow SDA to take full advantage of the many built-in features of the servlet platform as well as the many open-source libraries that support and extend servlet-based Web applications. This conversion will provide the basis for a number of enhancements:
- Provide a user interface that's more like a desktop application with rich, dynamic components (including Ajax components). At the same time, this will allow the simplification of the interface for beginning users by hiding more advanced options until they're needed.
- Support private user workspaces where an analyst can:
  - create recoded and computed variables and selectively share them with collaborators
  - save and share analysis options so a particular analysis can be easily recreated
- For archivists who are setting up an SDA archive, the installation procedure will be simplified by consolidating the SDA distribution package into a single Java Web application. The coordination of CGI and servlet-based components -- which can be tricky to configure -- will no longer be necessary.
What does this mean for organizations that already have SDA archives? What will change in the new SDA version -- and what won't? Most of the pieces of the current SDA architecture will remain the same as before. The SDA assets that organizations have developed -- such as SDA datsets, codebooks, etc. -- will be fully compatible with the new servlet-based Web interface. The things that WON'T change in the new architecture include:
- The SDA dataset format
- The SDA codebook format
- The DDL syntax. (DDL is SDA's native metadata format.)
- The HARC file syntax. (The HARC file is SDA's main Web configuration file.)
- All the non-CGI SDA programs
The things that WILL change are:
- The CGI programs (hsda, hsda2, etc.) will be replaced by a single servlet-based Web application
- The new SDA servlet-based webapp will run in a servlet container (such as Tomcat) rather than a plain Web server (such as Apache or IIS)
Charts
Charts were added to the output of the TABLES program in version 1.4 and to the MEANS program in version 3.4. Charts will also be added to the SDA 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.

Completed Projects

Complex Standard Errors
The calculation of standard errors for percentages and means in complex samples was revised to incorporate new developments for subpopulations and for differences. Complex standard errors for regression coefficients were implemented in phase 2 of this project. This was a joint project of CSM and the Substance Abuse and Mental Health Data Archive at ICPSR, University of Michigan.

Subset for Recoded and Computed Variables
The subset procedure was revised in SDA 3.3, in order to allow recoded and computed variables to be included in a subset dataset. A new CSV (comma separated values) output format was added, including a header record with the names of variables, to facilitate reading the dataset into a spreadsheet.

Disclosure Specifications to Protect Confidentiality
The analysis programs were modified in SDA 3.3 to suppress output that may compromise the confidentiality of survey respondents. The analysis programs will all read a 'disclosure.txt' file (if one has been created for a study), and they will enforce the specifications included in that file.

Search
Search functionality was added to SDA 3.2. Variable-level search can be done within a single study. Both variable-level and study-level search can be done across studies.

SDA Archiver
The Archiver is a Web application (released with SDA 3.1) that facilitates the work of adding new datasets and codebooks to an SDA archive. This application could be used both by administrators of a data archive and by individuals affiliated with member institutions who would like to set up their own dataset(s) in SDA.

New User Interface
A new user interface was developed for SDA 3.0 that includes program selection, variable selection, and program option choices all on the same screen. This was a joint project of CSM and ICPSR at the University of Michigan.

Quick Tables
Quick Tables is a simplified interface for obtaining analysis results. This was a joint project of CSM and ICPSR at the University of Michigan. For details about how it works, see the Quick Tables Information Page. You can also try generating a few Quick Tables for the GSS Cumulative Datafile from the SDA Archive page.

"Word" Format Codebooks
SDA 1.3 introduced a method of producing codebooks in Microsoft Word format. This new output option not only produces more attractive print codebooks -- with various fonts, heading styles, etc. -- but also allows users to easily introduce extra material, such as charts and other graphics, into print codebooks. Word-format codebooks are also a useful format because they can be automatically converted into PDF format using Adobe's Acrobat software. Here's an example of a small codebook produced by SDA 1.3 in Word format. And here's the same codebook after it's been automatically converted to PDF format (using Adobe Acrobat).

Instrument Documentation (IDOC)
CSM and the U.S. Census Bureau were involved in a joint project to construct Web-browsable documentation for CAI instruments. See the IDOC Web Site for more details and examples.