It’s confidential

How to avoid the Brickwall of Confidentiality when linking micro data

European Conference on Quality in Official Statistics, Vienna 2014

Jon Mortensen (jmo@dst.dk) and Søren Burman (sbu@dst.dk)

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Background

The Brickwall of Confidentiality

Challenges with confidentiality

The TEC and S-TEC pilot studies

Conclusion

Outline

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The paper is a specific response to developments toward very (we say, overly) detailed tables in the Trade by Enterprise Characteristics (TEC) and its service equivalent S-TEC

But we think the conclusions are generalizable to issues other than trade

Written by two compilers as ”a voice from the floor” so basically “air venting” from two middle-aged grumpy men

Background

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The disclosure /confidentiality dilemma: Access to high-quality data >< maintain confidentiality

Why confidentiality? Legal and ethical concerns, and Trust

Bottom line: The brickwall ensures that disclosed data is of high quality

The Brickwall of Confidentiality

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Identifying ”risky” cells is relatively easy

Ensuring that they are sufficiently concealed is the challenge Number of ways to suppress a single cell is V-1 * H-1

The difficulty of applying optimal secondary confidentiality increases with level of detail Automated process is often not up to the task

Challenges with confidentiality

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A leap in the detail level compared to the established TEC tables More dimensions and higher detail level

Pilot tables suffer from extensive confidentiality issues Sometimes more than half of the trade value is suppressed

In the end: Many hours used in producing and subsequently “destroying” the tables

The TEC and S-TEC pilot studies

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More information from existing data is a win-win, but…

…highly disaggregated, multidimensional tables are neither cost-effective nor useful due to confidentiality

We suggest:

Less detailed, preferably two-dimensional tables

Cross-border access to micro-data

Conclusion