The privacy threshold in action

Counts below N are hidden, rates disappear when either side of the fraction is hidden, and the export inherits the mask.

Synthetic data. The logic is the one used in production; the numbers are invented for this page.

Privacy threshold N: 5Any count below N is hidden. Move the slider and watch the bars, the rates and the export change together.

Learners who finished each session

A dashed outline marks a hidden count: it is drawn at the height of N, never at its real value.

Same data as a table, with rates
Session	Started	Finished	Completion rate
Session 1	48	41	85.4%
Session 2	33	24	72.7%
Session 3	21	12	57.1%
Session 4	9	below 5	below 5
Session 5	below 5	0	below 5

A rate exists only when both sides of the fraction are visible. Otherwise a visible rate next to a visible count would reconstruct the hidden one.

The export inherits the mask

session,started,finished,completion_rate
Session 1,48,41,85.4%
Session 2,33,24,72.7%
Session 3,21,12,57.1%
Session 4,9,below 5,below 5
Session 5,below 5,0,below 5

The mask lives in the aggregation layer, so the dashboard, the CSV and any report inherit it. There is no second place to forget.