HR Function

Alternatives to Bradford Factor for measuring absence

measuring absence

Image by Kaspars Grinvalds / Shutterstock, Inc


Many employers use the Bradford Factor to track absence and identify problems. But it isn’t the only way of measuring absence. In fact, a range of alternatives to Bradford Factor scoring exist, each with their own advantages and disadvantages.


I’ll be talking a bit about the Bradford Factor later on this page, but if you want to learn more about it right now, you can read our earlier article “What is the Bradford Factor?

The ‘Lost Time’ rate


One of the alternatives to Bradford Factor scoring, is the ‘Lost Time’ rate. This quite simply measures how much time you have lost to absence, as a figure compared to the maximum possible time employees would have worked for.


Let’s take a look at the calculation:


(Hours Lost) divided by (Potential Hours)


So, you can do this calculation using as many people as you like, over whatever period you like. For example, if you wanted to calculate the ‘Lost Time’ rate for a sales team of 10 people, over the course of a week. If the maximum number of hours per sales person per week was 40, you would have a Potential Hours figure of 400 (as there are 10 people). If one person had been off sick for a total of two days during that week, then your Hours Lost figure would be 16.


16 divided by 400 is 0.04 – or, 4 percent.


Benchmarking what is good or bad varies hugely on your industry or sector. But you might find it interesting to note that in 2017, the average UK worker lost 2.1 percent of their total working time to sickness.

The ‘Frequency’ rate


The ‘Frequency’ rate is another of the main alternatives to Bradford Factor. In contrast to the ‘Lost Time’ rate, it ignores the total time lost, and instead calculates how many individual spells of absence are occurring in your organisation.


One reason why some employers choose this method for measuring absence, is because a high frequency of absences – even if they are short spells – can be more difficult to manage and plan for.


To calculate the ‘Frequency’ rate, you do the following:


(Absence Spells) divided by (Total Employees).


So, if we used the same example as before, and calculated the ‘Frequency’ rate for a team of 10 sales people, where one person had taken two days off sick, then assuming the two days were consecutive, we would have an Absence Spells figure of 1. As there are 10 people in the team, we would have a Total Employees figure of 10.


1 divided by 10 is 0.1 – or, 10 percent.


Be careful when calculating ‘Frequency’ rate, and don’t try comparing the full year against one particular week or month. This is because the longer the period, the more Absence Spells you’ll be calculating – but without the number of employees necessarily changing. For example, you would score 10 percent for a one week period, but 20 percent for a two week period, even though the individual weeks themselves were exactly the same.


For this reason, it isn’t abnormal to get what seems like a very high percentage over longer periods. And due to the nature of the calculation, it’s even possible to calculate a score of more than 100 percent.

What is Bradford Factor scoring?


The above alternatives to Bradford Factor scoring look at specific issues – amount of lost time, and frequency of absences. What the Bradford Factor aims to do, is combine the two.


Bradford Factor uses both total time lost, and frequency of absence , to calculate a score that can indicate how disruptive specific employee absence patterns are for your organisation. It places a greater weighting on the frequency, and is best used for scoring individual employees.


However, you should be careful not to make instant judgements based on a high Bradford Factor score. It should be used only as an indication that you might want to check a particular employee’s situation, as there could be underlying reasons as to why an employee is having a high absence frequency (such as a disability). We discuss this further in our earlier article, Is the Bradford Factor Fair.

How to calculate Bradford Factor score


Here is what the Bradford Factor calculation looks like:


(Absence Spells) multiplied by (Absence Spells) multiplied by (Days Lost) = (Bradford Factor Score)


Here is the formula again, as a handy infographic which you may download and use however you wish:

05 Bradford factor


It’s worth noting that People HR calculates Bradford Factor scores for employees automatically, based on the absences recorded in their employee record. You can take a free trial here.

What is the best way of measuring absence?


If you want my honest answer? You should be using all three of these calculations. They all have their own advantages.

The ‘Lost Time’ rate can help you understand whether or not you have a general problem with seats on chairs.

 * The ‘Frequency’ rate can help you understand how disruptive the overall absence is in your organisation.

 * The Bradford Factor can show you where the most disruptive absence problems are coming from.


If you want to know how you’re performing compared to other companies in your industry, there’s some good advice on benchmarking sickness absence right here.