The formula
The score multiplies the number of separate spells of absence by itself, then by the total days:
B = S × S × D
- S - the number of separate absence spells over a period (usually the last 52 weeks);
- D - the total number of days absent over the same period.
Because S is squared, frequency dominates duration. The same ten days produce wildly different scores:
| Pattern | Spells (S) | Days (D) | Score |
|---|---|---|---|
| One spell of 10 days | 1 | 10 | 10 |
| Two spells of 5 days | 2 | 10 | 40 |
| Five spells of 2 days | 5 | 10 | 250 |
| Ten spells of 1 day | 10 | 10 | 1000 |
That is the whole idea: ten Mondays hurt the team more than one two-week spell, because every short absence breaks plans, shifts meetings and reshuffles other people’s work.
Thresholds people actually use
There is no official scale - the thresholds are conventions that companies adapt to their own reality. A common starting point: up to 50 is background noise; around 125 is worth a caring conversation; 250 and above deserves attention as a pattern. Treat these as tripwires for a conversation, not as verdicts.
Where the metric stops working
The Bradford factor counts patterns, not reasons. It cannot tell a fading commitment from a chronic illness, a difficult pregnancy or a parent with a sick child - and applied blindly, it punishes exactly the people who need support. In several countries, mechanical sanctions triggered by a score would also collide with employment and disability law.
Counting it without a spreadsheet
The arithmetic is trivial; the bookkeeping is not. To keep the score honest you need every absence recorded as a spell with dates, a rolling 52-week window, and the discipline to never miss a one-day sick leave - the exact kind of record-keeping that erodes in a spreadsheet by March.