The Bradford Factor is a formula that scores employee absence: B = S squared multiplied by D, where S is the number of separate absences and D is total days. The squaring of S gives more weight to frequent short absences than long ones. It is a useful flag but legally risky if used rigidly · most employers now use it as one signal alongside return-to-work meetings and case-by-case review.
What is the Bradford Factor?
The Bradford Factor (sometimes called the Bradford Formula or Bradford Index) is a scoring system designed to highlight short, frequent absences relative to long single absences. It is named after research undertaken at Bradford University School of Management in the 1980s, exploring the theory that frequent short absences are more operationally disruptive than long single ones.
The premise is intuitive. A team can plan around someone being off for 10 days with notice. The same 10 days taken as 10 separate single-day absences over a year is harder to cover, harder to predict, and often more disruptive overall.
The formula encodes that intuition by squaring the number of absences. Six single-day absences score considerably higher than one six-day absence, even though the total time off is identical.
The formula explained
- B = the Bradford Factor score
- S = number of separate spells (instances) of absence in the reference period
- D = total number of days absent in the same period
The reference period is usually a rolling 12 months. Some employers use a rolling 52 weeks, others use the calendar year. Whichever is chosen should be set out in the absence policy and applied consistently.
Worked examples
Four employees who all took the same total time off, but with very different scores.
Same total absence (10 days). Scores ranging from 10 to 1000. That spread is the whole point of the formula: it surfaces frequency in a way that a simple day count would not.
The classic comparison
The example most often cited in HR training:
- Employee A: 1 absence of 10 days → 1² × 10 = 10
- Employee B: 6 absences of 1 day each → 6² × 6 = 216
Employee B has been off less (6 days vs 10), but their score is over 20 times higher. That is the Bradford Factor in action.
Common UK score thresholds
There are no statutory thresholds. The numbers below are what most UK SMEs use as guidance. The actual numbers any employer adopts must be set out in the absence policy.
| Score range | Typical employer response |
|---|---|
| 0 to 50 | Generally acceptable. No action. |
| 51 to 100 | Informal wellbeing conversation. Check the employee is OK. |
| 101 to 200 | Formal absence review meeting. Discuss patterns and possible support. |
| 201 to 500 | First written warning under capability/attendance procedure. |
| 501+ | Final written warning or capability dismissal considered, after fair process. |
The HM Prison Service famously implemented the Bradford Factor in May 2001 and reported a 25% reduction in absenteeism over the years that followed. That success has been heavily cited by HR vendors but should be treated cautiously as a single case study with multiple confounding interventions running alongside.
The Equality Act risks
The Bradford Factor's biggest weakness is that it is blind to context. It does not distinguish between an absence caused by a hangover and one caused by epilepsy, asthma, mental health crisis, or pregnancy-related illness. Treat all absences identically and you create three substantial legal risks:
1. Indirect discrimination · section 19 Equality Act 2010
A blanket Bradford-based policy can amount to indirect discrimination if it places employees with a protected characteristic at a particular disadvantage and the employer cannot objectively justify it. The most common risk area is disability, where employees with chronic conditions like Crohn's disease, epilepsy, or migraine often have multiple short absences and reach high scores quickly through no fault of their own.
2. Discrimination arising from disability · section 15 Equality Act 2010
Treating an employee unfavourably because of something arising from their disability (where the employer knows, or should know, of the disability) is unlawful unless the employer can show it is a proportionate means of achieving a legitimate aim. Acting on a Bradford score that is high because of disability-related absence is exactly the kind of pattern that triggers section 15.
3. Failure to make reasonable adjustments · section 20 Equality Act 2010
Where the policy puts a disabled employee at a substantial disadvantage, the employer has a duty to make reasonable adjustments. ACAS guidance is explicit that adjusting trigger points (or excluding disability-related absence from the calculation entirely) may be a reasonable adjustment. Failing to do this is unlawful.
4. Unfair dismissal · Employment Rights Act 1996
Even where the Bradford Factor is used to support a capability dismissal, the employer must follow a fair process: investigating the reasons, obtaining medical evidence, consulting with the employee, considering reasonable adjustments. A Bradford score on its own does not establish capability. Tribunals expect employers to treat the score as a starting signal, not the conclusion.
What to exclude from the Bradford Factor
To stay on the right side of equality law, most employer policies exclude the following from the Bradford calculation:
- Pregnancy-related absence · required by section 18 of the Equality Act 2010. Penalising pregnancy absences is automatic discrimination.
- Disability-related absence · where the absence is connected to a disability under the Equality Act, the employer should consider excluding it as a reasonable adjustment.
- Statutory family leave · maternity, paternity, adoption, shared parental, neonatal care leave. None of these is sickness.
- Bereavement leave · including parental bereavement (Jack's Law) and the new general bereavement leave coming under the Employment Rights Act 2025.
- Time off for dependants · the day-one statutory right under section 57A of the Employment Rights Act 1996.
- Work-related injury · absences caused by an accident at work, especially where the employer has been notified through the relevant procedures.
- Hospital appointments and pre-booked medical appointments · particularly for ongoing conditions, where the employee gives reasonable notice.
- Compassionate leave · if the policy treats this as a separate category.
The exclusions should be set out clearly in the absence policy so employees know what to expect.
Honest pros and cons
Why some employers stick with it
- Operational signal · surfaces patterns of frequent short-term absence that cause real disruption to scheduling.
- Consistency · everyone is measured against the same formula, which can feel fairer than ad-hoc manager judgement.
- Simple to calculate · one formula, two inputs. Most modern absence software calculates it automatically.
- Behavioural effect · some employers report reduced absenteeism after introducing it, though it is hard to disentangle from other interventions like return-to-work meetings.
Why many employers are stepping away from it
- Legally exposed · tribunal claims under indirect discrimination, section 15 disability discrimination, and unfair dismissal are common when the formula is applied rigidly.
- Penalises chronic conditions · epilepsy, asthma, autoimmune disease, mental health conditions, all generate frequent short absences regardless of the employee's commitment.
- Encourages presenteeism · employees come to work ill to avoid hitting a trigger, spreading infection and reducing productivity.
- No diagnostic value · the score tells you that something needs looking at, but never what or why.
- Day-one SSP effect · the abolished waiting days mean more absences will be recorded, inflating scores across the workforce.
- Cultural impact · framing absence as a problem to be measured punitively can damage trust and engagement.
Better alternatives
Most modern absence policies combine three things rather than relying on a single score.
Often 3 or 4 separate absences in a rolling 12 months trigger a review meeting. Simple, easy to communicate, easy to apply.
For example, total of 10 days or more in a rolling 12 months. Catches different patterns the frequency trigger misses.
Probably the single most effective absence intervention. ACAS and CIPD both recommend it after every absence, including single-day ones. It signals attention without being punitive and surfaces underlying issues.
Treat triggers as the start of a conversation, not an automatic disciplinary process. Look at reasons. Consider reasonable adjustments. Engage occupational health early.
For the practical detail of return-to-work meetings, see our return-to-work interview policy template guide. For the broader sickness policy framework that all this fits inside, see our sickness absence policy template. And for pulling the absence figures themselves into a clean report, see how to report on staff absence and leave.
Using the Bradford Factor safely
If you decide the Bradford Factor still has a place in your absence management, here is how to reduce the legal risk:
1. Use it as a flag, never as a decision
A high score should trigger a review meeting, not an automatic warning. The decision to act must always rest on the meeting, the reasons for absence, and any medical evidence.
2. Document exclusions in the policy
Write down which absence types do not count towards the Bradford score. Pregnancy, disability-related, family leave, bereavement, time off for dependants, work-related injury, pre-booked medical appointments. Make this list visible to staff.
3. Adjust triggers as a reasonable adjustment
For employees with a known disability, consider raising the threshold or excluding disability-related absences entirely. ACAS guidance explicitly identifies this as a reasonable adjustment under section 20 of the Equality Act.
4. Be transparent with staff
Tell employees the formula, the thresholds, what gets excluded, and what happens at each trigger point. Surprise enforcement of any absence policy is a frequent cause of grievance and tribunal claims.
5. Pair it with return-to-work meetings
The Bradford score tells you there is a pattern. The return-to-work meeting tells you what the pattern means. Without the second, the first is dangerous.
6. Train managers
Line managers are usually the ones who first see a high Bradford score. They need training on the legal limits, how to handle disability-related absence, and when to escalate to HR or occupational health.
Sources
Frequently asked questions
What is the Bradford Factor formula?
The Bradford Factor formula is B = S squared multiplied by D, where S is the number of separate spells of absence and D is the total number of days absent over a defined reference period (usually a rolling 12 months). The squaring of S gives disproportionate weight to frequency. So 6 single-day absences score 36 (6 squared multiplied by 6 = 216), while 1 absence of 6 days scores 6 (1 squared multiplied by 6). The same total days, very different scores.
What is a high Bradford Factor score?
There is no legal definition. Common UK employer thresholds are: 50 or below means generally acceptable, 51 to 100 prompts an informal wellbeing conversation, 101 to 200 triggers a formal absence review, 201 to 500 may lead to a written warning, and 500+ might be considered for capability or disciplinary action. These figures are guidance only. The actual numbers any employer uses must be set out in their absence policy and applied consistently, with flexibility for disability, pregnancy and other protected characteristics.
Is the Bradford Factor legal in the UK?
The Bradford Factor itself is not unlawful, but using it rigidly can be. Tribunals have consistently held that mechanical application of the formula without considering the reason for absence can amount to indirect discrimination, discrimination arising from disability, or unfair dismissal. Risks under the Equality Act 2010 are highest where absence is linked to disability, pregnancy, or mental health conditions. ACAS guidance is clear that trigger points must not automatically start a disciplinary process.
What absences should be excluded from the Bradford Factor?
Best practice is to exclude pregnancy-related absence, disability-related absence (where adjustments under section 20 of the Equality Act apply), bereavement leave, statutory family leave (maternity, paternity, adoption), and time off for dependants. Including these in a Bradford score can amount to discrimination. Many employers also exclude absences caused by work-related injury, hospital appointments where the employee gives advance notice, and any absence covered by a return-to-work agreement. The exclusions should be set out in the absence policy.
Is the Bradford Factor a reliable indicator of attendance issues?
It is a useful flag but not a verdict. The score tells you frequency-weighted disruption, which can be a meaningful operational metric. What it cannot tell you is the reason for absence, whether the pattern is improving or worsening, or whether the employee has a long-term condition. Employers who treat a Bradford score as automatic grounds for action create legal risk. The intended use is as a starting point for a conversation, not the conclusion of one.
What is a better alternative to the Bradford Factor?
Most modern absence policies combine three things rather than relying on a single score: trigger points based on number of episodes (often 3 or 4 in 12 months) and total days, mandatory return-to-work meetings after every absence (which ACAS calls one of the most effective single interventions), and case-by-case review with consideration of reasonable adjustments. The Bradford Factor can sit inside that framework as one signal, but it should not be the framework itself.