I love the Runbritain rankings, other than that the site is not very reliable, because it gives you an indication of your running performance taking into account the conditions. If you run on a muddy course for example you will probably not get a good time, but the same is true for others. The Runbritain rankings take this into account so you can still get credit for your effort, in terms of a reduced handicap. I also like that only your five best performances are taken into account, so you can run slowly with a friend and not worry about harming your handicap (if indeed you ever worry about such things).

How does it work? I found it quite confusing. There is a video explainer by Tim Grose, one of the two leads for the team at Athletics Data that developed the rankings, but even this is not super clear in my opinion. The problem I think is that the normal view in the Runbritain ranking table for an athlete gives you, aside from the race name and time, two figures, SSS and vSSS. The SSS is the “Standard Scratch Score” and measure the state of the course, where zero is pretty much perfect and anything above 4 is fairly bad. 10 is the maximum and apparently it could be slightly negative though I have never seen that.

On a 5K such as a parkrun, each point is worth about half a minute so a score of 4 would mean most people are two minutes slower than they would be on a perfect course.

Second, the vSSS or virtual Standard Scratch Score shows how well you performed; this can be negative. More on this later.

These two figures though do not show you how the handicap is calculated. Handicaps run from maybe -10 (the lowest currently is -7) up to 54, based on golf handicaps, where lower is better. Imagine that you run a 5K parkrun in 25 minutes. This performance represents a basic handicap of 19.3 before adjustment, a figure calculated from senior age gradings but without looking at your age. Runbritain handicaps do not take account of age; they are purely about how fast you are in absolute terms. The exact table is not given though you could easily work it out.

This handicap is then adjusted based on two things, the SSS and the time penalty. The time penalty starts at -1.5 and gradually increases. To give an idea, an event one year ago has a time penalty of 2.5. So if you ran a 5K parkrun in 25 minutes today, and the SSS was 2.0, that would give you a handicap of:

19.3 -2.0 -1.5 = 15.8

If that event were a year ago it would come out at:

19.3 -2.0 +2.5 = 19.8

Your final handicap is the average of your best 5 handicaps after adjustment.

Since the vSSS is not part of this calculation, why is it shown? Well, it is kind-of part of the calculation because of the way SSS is calculated. Runbritain rankings does not go round inspecting each course and judging its condition. Rather, its algorithm looks at the results and at how each athlete did versus their expected best time (best handicap). This figure is called MySSS. So if you equalled your best handicap it would be zero, if you improved on it, it would be negative, and if you ran slower than it would be positive.

Gross says that “if you ran 20:00 for 5K (9.7 points) but your best 5K time is 19:00 (7.6), MySSS would be 9.7-7.6 =2.1”

There is a slight puzzle here because it is possible to get a PB (personal best) on a race but still have a positive MySSS, as I observe from my own results. The system will also record a MySSS even for a distance you have not done before. I believe this is because the system does not really look much at the distance, but mainly at your best handicap. Therefore if you ran a fantastic parkrun, lowering your handicap, and then got a PB on a half marathon but by less margin, your MySSS on the half marathon would be small but positive, being less fast than your best 5K time would have predicted.

Finally, Gross says that the MySSS is calculated based on “recent” results which is a good thing since what this part of the algorithm is really trying to calculate is how close to ideal the course was, and the fact that you would have run it faster 20 years ago is not relevant to that.

The algorithm looks at the MySSS for all the athletes and the middle one (median) becomes the SSS. Then your vSSS is your MySSS less the SSS.

There may be some slight inaccuracies in the above description but I believe the gist of it is correct. Grose refers to things like “mildly progressive” that suggest some small further adjustments.

Any flaws in this approach? I can think of a few. One is that there are many reasons for slower performance that are not to do with course conditions, such as illness, parkrunning with a pram, tailwalking (going last to sweep up any runners who have difficulties), and more. This presumably is why Runbritain rankings uses the median MySSS and not the mean, to calculate the SSS, but it will never be perfect.

Another issue is that parkrun is not a race – well, some treat it as a race and try for their best time, others more as a social event with dogs, prams, and chatting to a friend as they run. Nothing wrong with either approach, but that will impact the SSS and implies that someone who tries their hardest in a parkrun may have too low a handicap.

Despite imperfections though the system does work and I find it reassuring, after getting a slow time in bad conditions, that the Runbritain rankings view may show it in a more positive light.