Laserfiche WebLink
Attachment 3: HCA Small Numbers Standard <br />1. Why do we need a Small Numbers Standard? <br />It is the Washington State Health Care Authority's (HCA) legal and ethical responsibility to protect the privacy <br />of its clients and members. However, HCA also supports open data and recognizes the ability of information <br />to be used to further HCA's mission and vision. As HCA continues down the path of Data Governance <br />maturity, establishing standards such as this is key in helping HCA analysts and management meet the needs <br />of external data requestors while maintaining the trust of our clients and members and complying with agency, <br />state and federal laws and policies. <br />Publishing data products that include small numbers creates two concerns. As a reported number gets <br />smaller, the risk of re -identifying an HCA client or member increases. This is especially true when a <br />combination of variables are included in the data product to arrive at the small number (e.g. location, <br />race/ethnicity, age, or other demographic information). <br />Small numbers can also create questions around statistical relevance. When it comes to publicly posting data <br />products on HCA's internet site, or sharing outside the agency, the need to know the exact value in a cell that <br />is less than 11 must be questioned. <br />As the agency moves away from traditional, static reports to a dynamic reporting environment (e.g. Tableau <br />visualizations), it is easier for external data consumers to arrive at small numbers. Further, those external <br />consumers have an increasing amount of their own data that could be used to re -identify individuals. As a <br />result, more rigor and a consistent approach needs to be in place to protect the privacy of HCA's clients and <br />members. Until now, some HCA data teams have elected to follow small numbers guidelines established by <br />the Department of Health, which include examples of suppression methods for working with small numbers. <br />HCA is now establishing its own standard, but is planning to work with DOH and other agencies dealing with <br />healthcare data to try and develop a consistent small numbers methodology at a statewide level. <br />2. Scope <br />HCA often uses Category 4 data to create summary data products for public consumption. This Standard is <br />intended to define one of the requirements for a summary data product to be considered Category 1. <br />Specifically, it is intended to define the level of suppression that must be applied to an aggregated data <br />product derived from Category 4 data for the data product to qualify as Category 1. Category 1 products are <br />data products that are shared external to the agency, in large part those products that are posted on HCA's <br />Internet website (www.hca.wa.gov). The primary scope of this Standard is for those data products posted <br />publicly (e.g. on the website), or, shared as public information. <br />The following are examples of when this Standard does not apply to data products are: <br />a. Those shared directly with an external entity outside HCA, the Standard suppression of small <br />numbers would not be required. However, you should notify the recipient that the data products <br />contains sensitive information and should not be shared or published. <br />b. Those exchanged under a data share agreement (DSA) that will not be posted or shared <br />outside the Contractor. <br />c. Those created for HCA -only internal use. <br />This standard does not supersede any federal and state laws and regulation. <br />Washington State <br />Health Care Authority Page 21 HCA Contract No. K5885-1 <br />