Bradford Factor rules and edge cases
Rolling or fixed? Do weekends count? What about half days and part-timers? The mechanics nobody writes down - and every one of them is your choice, not a rule.
The Bradford Factor almost always runs on a rolling 52 weeks, counts only days the person was rostered to work, treats each continuous absence as one spell however long it lasts, and does not reset on 1 January. None of that is law - it is convention. But get the mechanics wrong and the score stops describing attendance and starts describing your record-keeping.
Does the Bradford Factor reset every year?
Not on a fixed date, no. The standard approach is a rolling 52 weeks: on any given day you look back one year, and absences drop out of the calculation as they age past that window. A score therefore falls on its own over time, without anyone doing anything.
Some employers do run a fixed leave-year window instead, which resets everyone to zero on the same date. It is simpler to explain and much blunter - somebody with five absences in December starts January clean, while somebody with five in January carries them for eleven months. If you use a fixed window, say so in the policy, because people will assume rolling.
What counts as one absence?
Each continuous period away is one spell, whatever its length. Off Monday to Friday is one spell of five days, not five spells. That is the entire point of the formula: three separate one-day absences (3² × 3 = 27) score far higher than one three-day absence (1² × 3 = 3).
- Off Friday and the following Monday - two spells, not one, unless your policy explicitly bridges a weekend. Say which, because this materially changes scores.
- A half day - 0.5 of a day, but still one whole spell. The spell count measures how often, not how long.
- Sent home mid-shift - usually a half day and a spell; again, only if the policy says so.
- An absence still running - most systems count the days taken so far and update as it continues.
Do weekends and bank holidays count?
Only days the person was due to work. Counting calendar days inflates every absence that spans a weekend and penalises part-timers hardest - somebody working Monday, Wednesday and Friday would have non-working days swept into every spell.
Bank holidays the person would not have worked should not count either. Nor should annual leave that happens to fall inside a period of sickness, though it is worth remembering that holiday keeps accruing during sick leave and can be taken during it.
How does it work for part-time staff?
Count rostered days, not calendar days - then the maths takes care of itself. But there is a fairness wrinkle worth knowing: a part-timer absent for one of their three working days has lost a third of their week, while a full-timer absent one day has lost a fifth. The raw score does not know that.
Some employers pro-rate thresholds for part-time staff for exactly this reason. If you do not, at least look at whether your triggers are catching part-timers disproportionately - that pattern is worth spotting before somebody else spots it for you.
What should never enter the calculation?
| Type of absence | Counts? |
|---|---|
| Ordinary short-term sickness | Yes |
| Pregnancy-related sickness | Never - counting it is automatic discrimination |
| Disability-related absence | Usually excluded, or the threshold is adjusted |
| Statutory family leave | No - it is not sickness |
| Time off for dependants (ERA 1996 s.57A) | No - a statutory right in its own name |
| Annual leave, TOIL, appointments | No |
| Industrial injury | Most policies exclude it |
When you exclude something, remove the spell as well as the days. Dropping three excluded days but leaving the absence in the spell count still inflates the score, because the spell count is squared. Full detail in Bradford Factor exclusions.
Where should the rules be written down?
In the absence policy, in plain terms: the window (rolling or fixed), what counts as one spell, how weekends and half days are treated, what is excluded, the thresholds, and what happens at each. Every one of those is a choice you have made rather than a rule you inherited - and the first time a score is used in a difficult conversation, somebody will ask.
Work out a score with the Bradford Factor calculator, and see the main guide for the formula, the published thresholds and the fairness caveats.
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Rules applied the same way every time
CoDash scores absence on a rolling 52 weeks from each person's real working pattern - half days, part-timers and exclusions handled without anyone doing the arithmetic.