There are four ways to access data. Not all ways are available for all study files.
Public-use Microdata Files
Public-use files (PUFs) are microdata files constructed from the restricted-use data files by treating the data with confidentiality protections. The exact confidentiality protections vary by data program and more information on specific data treatments is located in the corresponding codebook. PUFs are publicly available and can be downloaded on SAMHDA by study and year by selecting Data > Browse Studies or Data > Browse Series from the toolbar.
Public-use Data Analysis System (PDAS)
PDAS is now available and ready for use. PDAS is a user-friendly online analysis tool for users to analyze public-use data. This tool allows users to review study variables, run crosstab analyses, perform logistic regressions, and download the results of any analysis to CSV format. PDAS is populated with the PUFs and may not contain all variables of interest. No files need to be downloaded.
Restricted-use Data Analysis System (RDAS)
RDAS is an online tool for users to output custom crosstabs using pooled years of restricted-use data that pass built-in confidentiality restraints. It is similar to the publicly-accessible PDAS tool, except it is populated with restricted data, including certain geographic identifiers, like state. Single year estimates are not available through RDAS. Only the NSDUH data will be available in the initial release of RDAS.
RDAS contains most of the variables available on the full NSDUH restricted-use file (RUF). Some exceptions include individual weighting components and pair relationships. RDAS will have data up to 2015 and as far back as 2002.
RDAS will be available to anyone who is willing to create a user account and can be accessed anywhere in the world. RDAS data is restricted so users cannot view the actual microdata and it will not return results that fail to comply with SAMHSA's disclosure limitations.
Restricted-use Microdata Files
The Data Portal will offer researchers access to the full restricted-use datasets (i.e., microdata) for both NSDUH and DAWN. Researchers will be able to apply for access to the Data Portal during an application period and must agree to special permissions to protect identifiable data from disclosure. The Data Portal grants access to the full RUF for each survey year. The Data Portal is the only way to access state data for an individual year and it requires the support of a U.S. institution on U.S. soil.
There will be an application process for access expected sometime in 2018.