Daniel BecklerUnited States Department of Agriculture

National Agricultural Statistics Service

Timothy MulcahyNORC at the University of Chicago

Topic (ix): Statistical disclosure limitation for table and analysis servers: how to make outputs of modern data access infrastructures safe

Slide 1Slide Slide 1UNECE/Eurostat Work Session on Statistical Data Confidentiality

Tarragona, Spain • 26-28 October 2011

DATA UTILITY, CONFIDENTIALITY, AND THE PRODUCTION-POSSIBILITY FRONTIER:

STRIKING A DELICATE BALANCE

Overview of Microdata Dissemination Techniques

Public Use Files

Online Statistical Data Cubes and Tabulation Engines

Remote Batch Processing

Synthetic Microdata

Remote and Physical Data Enclaves

Slide 1Slide Slide 2

With these methods, there is a trade-off between disclosure risk, the amount of analytic utility, and the ease of access.

UNECE/Eurostat Work Session on Statistical Data ConfidentialityTarragona, Spain • 26-28 October 2011

National Agricultural Statistics Service

United States Department of Agriculture

Conducts censuses & surveys on U.S.’s farm population.

Generates official USDA agricultural statistics, many impact global commodity markets

Paper discusses how NASS protects the confidentiality of microdata, while providing as much analytical utility as possible to the users of the official statistics as well as researchers.

Slide 1Slide Slide 3UNECE/Eurostat Work Session on Statistical Data Confidentiality

Tarragona, Spain • 26-28 October 2011

United States Census of Agriculture

Conducted every 5 years. Produces very detailed data at the U.S., state, and county (i.e., sub-state) levels.

Data for individual agricultural operations are protected from disclosure in published totals by using a threshold rule and a dominance rule

Primary suppressions result directly from these rules

Complementary suppressions are then determined to ensure primary suppressions may not be calculated from published data.

Slide 1Slide Slide 4UNECE/Eurostat Work Session on Statistical Data Confidentiality

Tarragona, Spain • 26-28 October 2011

United States Census of Agriculture

Loss of utility of the Census due to suppressions:

Slide 1Slide Slide 5UNECE/Eurostat Work Session on Statistical Data Confidentiality

Tarragona, Spain • 26-28 October 2011

DomainOverall Count of

Estimates

Number of Primary

Suppressions

Number of Complementary

Suppressions

Total Number of Suppressions

Total Suppressions as

% of Estimates

US 29,075 255 351 606 2.08

State –Low % 61,000 8,614 2,721 11,335 18.58

State – High % 16,095 5,111 2,195 7,306 45.39

All (US & State)

2,556,586 430,843 151,506 582,349 22.78