Following on from my blog about BGR completions for 2019 (and previous years) I have had look at weather data for the last 10 years to see if one can infer any relationship between weather in the Lakes and BGR completion levels. [NB: I am quite prepared to accept that this analysis shares some pretty dodgy statistical analysis]
Firstly, I made an assumption (extrapolating from the monthly data of completions) that the most significant months of any year would be May to September. I then calculated the average rainfall (in mm) for those months for each year from 2010 to 2019, and plotted this against the numbers of completions for those years. The hypothesis being that wetter years would have lower numbers of completions.
In the resulting graph [above] the orange line is numbers of completions (not % but absolute numbers) and the blue line is rainfall (in mm, as per calculation above). For the hypothesis to be true the high rainfall years would have less completions. It can be seen from the right of the graph that for 2017, 2018 and 2019 this does not follow. 2017 and 2019 are high rainfall – high completions, and 2018 is conversely low rainfall – low completions. For 2010, 2011 and 2012 it varies from fitting the hypothesis for 2012 (high rainfall lower completions – but see 2013 onwards), and sort of fitting for the 2010 (low rainfall, moderately high completions), to no pattern for 2011. For 2013 to 2016 it seems that it is counter-intuitive, in that the completions goes down with low rainfall and up with higher rainfall.
Being not satisfied with this aspect I moved on to look at one year, month by month, to see if the was any inferable weather effect there.
Taking the monthly completions data and monthly actual rainfall data, I plotted the two against each other for the year of 2019.
In the resulting graph [above] the left axis and blue line is rainfall and the right axis and orange line is the number of completions for that month. [The months are numbered from1 to 12 along the bottom axis, representing Jan to Dec] The completions line is a normal curve, showing the normal distribution you would expect of completions data (ie more in summer months and less in winter, peaking this year in June). The rainfall shows three peaks in March, Aug/Sept and Dec. At a stretch you could argue that the March peak drags the completions data lower than it might have been – there is a small downward bulge in the curve for that month. Similarly the August peak also produces a dip in (expected) completions.
At the end of the day it has proved to be not a particularly meaningful analysis. I have made some pretty big assumptions, for instance that rainfall would have an immediate effect on completion numbers, and used a fairly small data set – so will accept any criticisms of my methodology. Looking back, it may have better to plot, say, June/July/August rainfall against the completions data as that might well have a better correlation, as that is when more people plan their rounds. Thoughts or counter suggestions welcomed, through the ‘Comments’ link.
If anyone wants to look further, the data is available. See: here for BGR completions data [this year is the first time by month data has been published), and here for the weather data [which is for the weather station at Newton Rigg, and includes max temp, min temp, and hours of sunshine for each month, going back to 1959].
Credit: Steven Thurgood for the weather station link via Facebook.
Bob Wightman has just released the figures for Bob Graham Round (BGR) registrations, completions, male/female split, direction of travel, etc. for 2019, which make interesting reading, and that I have commented on before. [https://forum.fellrunner.org.uk/showthread.php?24761-BGR-2019-summary&p=657211#post657211]
I have updated my spreadsheet, and the graphs of several aspects of the data. My original analysis was in an earlier blog [BGR completion rate is 42%], with a follow-up on women’s completions [Women’s completions at BGR]. Both were based on data up to and including 2018.
Below are some updated graphs and a couple of comments on each.
This first graph shows the data just for completions since 1971. The black line is the actual numbers completing, which was at its highest ever level in 2019, after a minor downturn in 2018. [The red line is the trend line which is obviously up (after recovering from the Foot and Mouth blip of 2001) and the blue is the moving mean]
More recently figures for registrations and completions have been published, allowing analysis of completion percentages. The graph above is of the last 8 years, showing upward trends in registrations and completions (these figures are for males and females combined), but interestingly NOT an increasing percentage actually completing. It invariably hovers either side of 50%. The next two graphs look at the male/female data.
The men’s data pretty much follows the pattern of the total data (there are still many more men than women involved). 2019 shows a rise in all three data sets for the year, after all going down in 2018. The completion rate of 54.95% for men is the highest ever since I have been looking at this (the second highest was 52.5% in 2012). The male completions, at 111, is the highest it has ever been in one year.
The women’s completions (red) have been the similar recently (13, 13, 14 and 14 in the last 4 years), but because the registrations have been going down (28, 27, 24, 22) there has been an increase in completion percentage for the last 4 years. The percentage lines are at the top of this graph as the numbers are higher than either the registrations or completions, but do clearly show that trend, which ended up with an impressive 63.64% completion rate for women this year, the highest ever, male or female, ever recorded. Admittedly from a small sample size.
While I am here, and apropos of nothing in particular, and not directly related to anything above, but there was an interesting article in the Guardian recently by Kate Carter that highlighted some ‘female ultra-athletes leading the field’ that they compete in, including the incomparable Jasmin Paris, whose blog on her Montane Spine race win is well worth a read.
Following on from my post BGR completion rate is 42.2% a couple of people mooted the idea that the women’s completion percentage might be higher, giving reasons such as: ‘they’ve generally prepared better; they don’t sprint the first two legs and then run out of steam on leg 3; they are stronger’ (h/t Paul Wilson). The Bob Graham Club website has data for the last 7 years by gender, so I have graphed it for women only.
Comment: All three sets of data – percentages, registrations, and completions are all trending slightly upwards (the dotted lines). The completion percentage varies significantly for women from year to year, which might be partly explained by the small sample size – meaning that one person swinging from succeed to fail would change the resulting numbers a fair bit. The lowest % is 31.6 and the highest is 60.0 (for all completions in the same period it ranged from 39.6 to 53.6%). Although the percentage for 2018 is high, at 58.3%, only in three of the seven years is the women’s percentage higher than the overall percentage. To me that is inconclusive and doesn’t really prove the point.
[Yes I know I should compare women to men and not the overall completers, so here is the men’s data graphed]
Comment: not much to say, except that it almost exactly mirrors the original graphs for all completers regardless of gender. It does show that although registrations and completions for men are trending upwards, the percentage completions is slightly down-turned, and is consistently around the 50% mark (with a range of 40.8 to 52.5).
A little wrangling of the figures that BGR club post on their website for registrations and completions for the Bob Graham Round shows that the completion percentage is trending downwards at present. For 2018, 199 people registered and 84 completed, which is a 42.2% success rate. I have graphed the figures for the last 7 years* and the picture shows the trends for registrations, completions and percentages (the three dotted lines, which for the mathematicians amongst you are simple linear trend lines).
Comment: Registrations have been steadily increasing, with a high of 233 in 2017. It was a small dip last year, but still the second highest. Completions mirror the registrations pattern, again with a high of 115 in 2017, with last year again the second highest. Despite these fluctuations and trends, the % of completions does seem to always remain pretty much the same. It varies from 53.7% in 2012 to 39.6% in 2014, and as noted is marginally trending downwards. Speculative (and possibly controversial) cause – more less-prepared aspirants having a go these days.
A second graph shows the number of completions for every year since 1971.
Comment: the graph shows a strong trend for more people completing the BGR (solid red line is the linear trend) over time, but also how it fluctuates from year to year (dashed blue line is a 6-year moving average). 2001 was the year of foot and mouth disease, when there were no completions. It is interesting how long it took to get back to previous levels after that, presumably as folk weren’t able to get on the hills to recce. In the 1990s the numbers fluctuated greatly but were in fact trending down for some reason. The graph also shows that the 115 completions in 2017 were the highest ever number.
*NB: these are the only detailed ones I have access to
Notes/links: For more on the Bob Graham Round see the club website at: http://www.bobgrahamclub.org.uk/. For more on the BGR and its history see my book: ‘The Round: in Bob Graham’s footsteps’. For more on Kilian Jornet’s outstanding new record of 12-52 for the round, which he set in 2018, see: ‘Kílian Jornet smashes Bob Graham endurance race record’.
Caveat: I am aware that posting this I may be accused of ‘promoting’ the BGR, something the Bob Graham Club disapprove of. They rightly point out on their website some of the issues that increasing numbers cause, one of which is illustrated below.