HR departments often use the Bradford formula to calculate the impact of absence. But how does it work, and is it still a valid metric?
What is the Bradford factor and what is it used for?
The Bradford factor is a formula used by HR departments to calculate the impact of employees’ absences on the organisation. It is based on the theory that short, frequent, unplanned absences are more disruptive to organisations than longer absences.
How are Bradford factor scores calculated?
Bradford factor scores are based on the frequency and length of an employee’s absence during a defined period, usually 52 weeks.
The formula used is:
B= S² x D
B = Bradford factor score
S = total number of spells (instances) of absence for that individual in the given period
D = total number of days the individual was absent during the given period
Some HR systems, such as CIPHR, can automatically calculate this score for you. Free online calculators are also available.
What is a ‘good’ or ‘bad’ Bradford factor score?
Higher scores suggest an employee’s absence rate is having a more negative impact on the organisation.
For example, if an employee is absent once in 52 weeks for 10 days, their Bradford factor score is:
(1×1) x 10 = 10
If an employee is absent twice in 52 weeks for five days at a time, their Bradford factor score is:
(2×2) x 10 = 40
And if an employee is absent 10 times in 52 weeks for one day at a time, their Bradford factor score is:
(10×10) x 10 = 1,000
In these three scenarios, the employee has been absent from work for the same length of time, but the shorter, more frequent absences generate a higher Bradford factor score.
How useful are Bradford factor scores?
Some employers choose to set thresholds at which Bradford factor scores are deemed to be problematic and require interventions such as verbal and written warnings and, potentially, dismissal. Such thresholds are often designed to discourage employees from taking unnecessary sick days.
But organisations must make sure there are safeguards in place to protect employees with medical conditions – such as cancer – that may cause irregular absence patterns because of hospital appointments. Employers must also make sure that their absence policies (including their use of Bradford factor scores) do not discriminate against employees with disabilities. Employees are legally entitled to time off to care for dependents, so these unplanned absences should not be included in Bradford factor calculations.
This article was first published in November 2014. It was updated in April 2018 for freshness, accuracy and clarity.
Read this next
With absence and presenteeism estimated to cost the UK economy £73 billion annually, ensuring employees’ wellbeing is a business imperative. Samantha Caine shares her top tips for preventing stress and burnout among your staff