A blank map can be misread
If a county has no displayed rate, it may have too few events for stable reporting rather than no events at all. Coloring that county as the lowest-risk area would create a false comparison.
Use a distinct label for suppressed or unavailable data.
Rules differ across products
CDC's U.S. Cancer Statistics uses specified suppression rules for small counts and rates. Other datasets use different thresholds or methods. Do not copy one product's rule into another without checking its documentation.
Protect the purpose of suppression
Sometimes additional cells are withheld so the hidden value cannot be recovered by subtraction. Attempting to reconstruct it from totals defeats the confidentiality protection.
| Display category | Meaning to preserve |
|---|---|
| Zero | No recorded events under the definition |
| Suppressed | Value intentionally withheld |
| Missing | Information unavailable for another reason |
Consider a more suitable summary
Combining years or categories may produce a more stable, publishable estimate when allowed, but it changes the question and can hide local differences. Document that tradeoff.
A useful report keeps absence of publication separate from absence of a health problem. Otherwise, the places with the least reportable information can incorrectly appear to have the least need.
