For Guts or for Glory: was the 2021 Tour de France attrition influenced by the upcoming Olympics?

When looking at the withdrawals from the 2021 men's Tour de France; there were a lot, but not that many more than in 2020 - (details here - https://fulltimesportsfan.wordpress.com/2021/07/21/tour-de-france-2021-data-doodles-week-3/). One possible question was "is the increase in withdrawals due to the 2021 course being harder, or because people were more willing to drop out than usual because of the up-coming Olympics?" 

@rorygaron (https://twitter.com/rorygaron) on Twitter suggested a good comparison that might answer the question - look at the withdrawals from the 2021 Giro Rosa. 

In many ways, it's a perfect comparison, the Giro Rosa being the most well known women's race, it being another grand tour that was just before the Olympics. However, it was likely to have fewer "I'll drop out so as not to risk my Olympics" drop outs because it was further away from the Olympics (finishing on the 11th of July vs the 18th of July, with the first of the Olympic road cycling events on the 24th of July). 

The plan was to map out the Giro Rosa withdrawals, and see if their pattern matches the 2020 or 2021 men's TDF more, the idea being that: 

If the curve for the 2021 Giro Rosa resembles the 2020 men's TDF pattern, the increased withdrawals in the TDF could have been due to increased "Olympic" withdrawals.  

If the curve for the 2021 Giro Rosa resembles the 2021 men's TDF pattern, no, the increased number of withdrawals are probably due to the race conditions. 

There are, of course, certain caveats, the Giro Rosa is over a smaller distance, there are smaller teams and due to funding (or lack thereof) there is less technical support e.g. soigneurs etc so it can be harder for the racers to overcome wear and tear damage. There is also one more team in the Giro Rosa than in the men's TDF.

Riders remaining at the end of the 2021 Giro Rosa

   

3 of the teams were completely wiped out with no riders reaching the finish while 3 teams had no drop outs at all.

Withdrawals by stage 

   

Looking at this chart, my first reaction is WTF happened in stages 4 and 10. I looked it up, stage 4 appears to have been an unfortunate mix of difficult time trial with a very fast winner, but from the stage profile, what happened with stage 10 is inexplicable, I mean yes it was the stage after the queen stage but still. One possible cause for the late attrition is that the Giro Rosa, unlike the TDF, was not split into weeks and there were no rest days.

Kaplan Meier chart of all withdrawals

   

You can see the effect of stage 4 in the overall Kaplan Meier.

Team Kaplan Meier

   

Looking at the team version, my first question is what happened to Team TIBCO-SVB? It turns out that both they and Bizkaia Durango had to withdraw their teams due to COVID - Article on Tibco and the article on Bizkaia Durango.

Reasons for Withdrawals

   

The Giro Rosa had more morning Did Not Starts than the men's TDF (36% vs 21%), ~ the same percentage of mid-stage abandonments/DNFs (40% vs 42%) and fewer Over Time Limit withdrawals (24 vs 37% - and all of those were in the same stage, stage 4). 

If we compare the rate of withdrawals, the Giro looks much worse.

   

 However, if we the spread the points out so that they cover the same time span (cheating I know, that's why I've not joined the points up on the "roughly relative curve"), the curves don't look all that different until right towards the end of the Giro Rosa, when we know there were at least a couple of Olympic dropouts. 

 

So, what can I say from this? Mostly that the jury is still out. 

One obvious further check would be to do the same thing for the 2020 Giro Rosa and see if there's a difference. 

For the data on withdrawals, what type they were and which stage they happened on, I relied on Pro Cycling Stats - https://www.procyclingstats.com/race/giro-d-italia-femminile/2021/gc/startlist/roster-with-dropouts 

https://www.procyclingstats.com/race/giro-d-italia-femminile/2021/gc/stages/all-stage-profiles https://www.procyclingstats.com/race/giro-d-italia-femminile/2021/gc/stages/winners 

 For the explanations as to what happened on each stage, I found Cycling News invaluable.