How the Bradford Factor works
The Bradford Factor (sometimes called the Bradford Formula or Bradford Index) is an absence measure associated with research at the University of Bradford School of Management in the 1980s. Its idea is simple: short, frequent, unplanned absences usually disrupt work more than a single longer absence, because each one needs last-minute cover. Squaring the number of spells makes frequency count much more than duration.
Worked example: same 10 days, very different scores
| Pattern | Spells (S) | Days (D) | Score (S² × D) |
|---|---|---|---|
| One 10-day absence | 1 | 10 | 10 |
| Five 2-day absences | 5 | 10 | 250 |
| Ten 1-day absences | 10 | 10 | 1,000 |
All three employees lost the same 10 days. The score separates the pattern that needs a conversation from the one that was a single illness.
Example trigger points
There are no official thresholds. Employers set their own in their absence policy. This example scale is widely quoted:
| Score | Example action |
|---|---|
| 0 to 50 | No action |
| 51 to 200 | Informal return-to-work conversation |
| 201 to 400 | Formal absence review meeting |
| 401 to 600 | Further formal review, support plan |
| 601 and above | Final stage under the absence policy |
Using it fairly
- Exclude protected absence. Absence related to disability, pregnancy or maternity should be handled separately. In the UK this falls under the Equality Act 2010.
- Start with a conversation. A high score is a reason to ask what is going on, not proof of a problem.
- Look at the pattern, not just the number. Repeated Mondays, Fridays or days around holidays tell you more than the score alone.
- Use a rolling period so old absences stop counting.
The score is one input. The absence rate shows how much time a whole team loses, and the cost of absence calculator shows what that time costs. To track all three automatically across every employee and site, see attendance and absence patterns.