Data Suppression Rules

Data Suppression Rules

  • Public education reports offer the challenge of meeting transparency requirements while also meeting legal requirements to protect each student’s personally identifiable information (PII). Recognizing this, the reporting requirements state that disaggregation of the data may not be published if the results would yield personally identifiable information about an individual student. While the data used by the DDOE and Local Education Agencies (LEA) is comprehensive, the data made available to the public is masked to avoid unintended disclosure of personally identifiable information at summary school, LEA, or state level reports.

    Pursuant to the Family Education Rights and Privacy Act (FERPA) (34 CFR §99), the DDOE applies the following statistical methods to avoid disclosure of personally identifiable information in aggregate reporting.

    1. For all data, counts for groups or subgroups with 15 or fewer students are suppressed and represented by “-” in data reports. Complementary suppression of one or more non-sensitive cells in a table may be required so that the values of the suppressed cells may not be calculated by subtracting the reported values from the row and column totals.

    2. Only report percentages for grade level reporting within a school and district.

    3. Percentages are suppressed when the underlying student counts can be derived for groups or subgroups with 15 or fewer students (i.e., if the number tested and proficient are reported, then the percentage may need to be suppressed).

    4. Any percentage above 95 or below 5 will be reported as >95% and <5%, respectively.