What enhancements have been made to SDA?

SAMHDA uses Survey Documentation and Analysis (SDA) version 3.5. A log of updates included in versions of SDA released since 2009 follows.

SDA 3.5 (released April 2011)

For the REGRESS and LOGIT programs, enhancements include:

1. Computation of standard errors for complex samples using the jackknife repeated replication method.
2. Ability to create multiple dummy variables for each value of a numeric variable in a single command.
3. Option to request confidence intervals (90%, 95%, or 99%).
4. Option to display the variance/covariance matrix of the regression coefficients.
5. Ability to suppress the list of independent variables.

Content adapted from the SDA Manual (SDA 3.5).

SDA 3.4 (Released January 2010)

For the TABLES program, enhancements include:

1. Corrections to the calculation of standard errors and confidence intervals.
2. Addition of Rao-Scott F-tests.
3. Ability to display weighted or unweighted N of cases.
4. Option to set the number of decimals for all statistics.

For the MEANS program, enhancements include:

1. Corrections to the calculation of the standard errors and confidence intervals.
2. Option to display the p-value of each difference from the cells in a base row or column.
3. Default reporting of the weighted N of cases in each cell for weighted analyses.
4. Option to include charts in output.
5. Optional diagnostic table for design variables.

Content adapted from the SDA Manual (SDA 3.4).

SDA 3.3 (Released June 2009)

1. Disclosure Protection: SDA has the ability to suppress output that may compromise the confidentiality of survey respondents by applying disclosure protection rules to a data file. Analysis programs, including RECODE and COMPUTE, check for disclosure risk through use of disclosure rules. Disclosure rules may be specified to: a) prevent an analysis from being run; b) suppress the output after running an analysis; and c) suppress the unweighted number of cases from being reported in the output. The SDA 3.3 Documentation for Disclosure provides greater detail on the disclosure rules that may be specified. SAMHDA data files with disclosure protection rules in place are available in the Restricted-use Data Analysis System (R-DAS), which is based on the SDA platform.
2. List Created Variables - View Button: The output from the listing of recoded and computed variables now includes a "View" button that provides access to descriptions of the variables. This feature can be accessed under the SDA Create Variables menu.
3. Title: A title or label can be entered for each analysis request and will appear at the top of the HTML output produced by SDA analysis programs.
4. Customized Subset: This procedure has also been revised in that recoded and computed variables may now be included in a subset. If pre-set selection filters have been defined by SAMHDA, these filters now apply to the interactive version of the subset procedure as well as to the analysis programs. A Comma Separated Values (CSV) file is available for output.

Content adapted from the SDA Manual (version 3.3)

For further information on SDA, please select the Getting Started button from the SDA menu or consult the Online Analysis Using SDA page.