Community Data Profiles Suppression
Suppression rules are not utilized in the Profiles. Internal analysis is used to determine the appropriate number of years required to protect confidentiality in this system. In MOPHIMS, the Profiles will continue to show indicators for relatively rare events, even if the same indicator with the same selection parameters would be suppressed in the Missouri Information for Community Assessment (MICA) Data MICAs. Internal review and analysis will continue in order to ensure that the risk of identifiable information being released through the Profiles is minimized.
Conditionally Exempt Variables in the Data MICAs
It is important to display as much information as possible in the MOPHIMS system so stakeholders can determine the overall impact of health conditions and factors impacting health. At the same time, MOPHIMS should suppress enough data so that personally identifying information cannot be determined through use of the tools.
As such, variables/indicators have been designated as exempt or conditionally exempt from the confidentiality rule so stakeholders can conduct a proper analysis. If a table is generated using only variables/indicators from the exemption list, suppression will not apply to that table even when small numbers are generated. If a table is generated using more than two variables/indicators from the conditionally exempt list and the cell count is below the suppression threshold for that Data MICA, then suppression rules would be applied. The lists of exempt and conditionally exempt variables will vary across Data MICAs but all follow the same general patterns. (Appx- Emergency Room MICA: Exempt and Conditionally Exempt Variables)
Data MICA Tables and Cell Types
Data MICA table output consists of inner cells and total cells. (Appx-Figure 1) Suppression is applied separately to the inner and outer (total) cells of a MICA table. Most Data MICAs have a suppression threshold of four. Values less than or equal to four (not including zero) will trigger/initiate suppression. (Appx- Current MOPHIMS System Suppression Thresholds) In order to prevent algebraic calculation, if the sum total of rows/columns triggering suppression is greater than one but less than three, the three rows/columns with the lowest row totals are suppressed.
Inner Cell Suppression
Suppression will be applied to the inner cells of either the row or the column depending on the chosen layout of the MICA table. As a default, suppression will be applied only to the rows, except in cases where the table has more columns than rows. If the table has more columns than rows, then suppression will primarily be applied to the columns.
If a table contains three or fewer rows/columns and suppression is invoked, all of the inner cells of that table will be suppressed. (Appx- Figure 2)
If a table contains four or more rows/columns, any inner cell that is less than or equal to the suppression threshold (but greater than 0) will be suppressed. If the total number of rows/columns that trigger suppression is at least one but less than three, the inner cells in the three rows with the smallest row totals must be suppressed. (Appx- Figures 3 and 4)
Suppression of Row/Column Totals
If an outer row/column total is less than or equal to the suppression threshold, it will be suppressed along with the inner cells in that row/column. If an outer row/column total is greater than the suppression threshold, the outer row/column will be displayed, even if all of the inner cells in that row are suppressed. (Appx- Figure 5)
Suppressing Charts and Maps in MOPHIMS
If a chart is to be created in MOPHIMS from a table that has suppressed data that chart must also be suppressed in its entirety with a footnote notifying users that the chart was suppressed due to confidentiality concerns.
When mapping information from the Data MICAs, geographies with suppressed data should be shaded the appropriate color for whichever category they may fall. However, the geography’s data should be suppressed in the data table shown below the map, and the count, rate, and confidence intervals should be suppressed in the map’s hover box.
‘Unknown’ Values in MOPHIMS
‘Unknown’ rows/columns will not trigger suppression. However, they will otherwise be treated the same as other values that do not trigger suppression and may be used to suppress additional rows/columns in a table with low counts.
Appendix
Examples in this appendix use a mix of true and fictional data.
Figure 1. Inner Cells versus Total Cells
Inner cells shown in orange. Outer (total) cells shown in blue.