After a record number of qualified applicants applied to run the Boston Marathon in 2024, there has been plenty of talk about what will happen in 2025.
I made a prediction about the cut-off time here (7:03), and I added some additional data and context here.
With the registration period under way, runners are eager to know whether or not they’ll make the cut. And where there’s uncertainty, there’s fuel for fiery discussions on the Internet.
I’ve noticed a few theories floating around that people tend to latch on to. One is the Easter effect, which I dealt with in a previous post. Another is the Boston 2024 effect.
In isolation, the results of the 2024 Boston Marathon would seem to have a huge potential impact on the cutoff time. When you look at the big picture, though, this simply isn’t the case.
Nonetheless, I’ve seen some people double down on this idea in arguments about the cut-off time. They insist it simply can’t be true that the cut-off time will remain deep after runners made such a poor showing in Boston this year.
Today, I’m here to show my work and double down on the idea that despite the results of the 2024 Boston Marathon there will still be a record number of applicants for the 2025 Boston Marathon.
Why Do People Think the 2024 Boston Marathon Matters So Much?
Let’s start with understanding the assumptions behind the argument.
First, the Boston Marathon is the number one marathon yielding applicants to the Boston Marathon. The BAA lists it on their website as a top qualifying race, and when they announced the field for 2024 they clearly identified the list of the five most popular qualifying races (Boston, Chicago, London, Berlin, and CIM).
It’s not hard to see why this would be the case.
The Boston Marathon has the largest field of fast runners, with over 20,000 runners who are already capable of beating their own Boston qualifying time. Combine that with the selection effect – whereby people who actually run Boston are more likely to want to run Boston – and people who qualify at Boston are more likely to follow through with an application than someone who qualifies at another race (like Berlin).
Joe Drake did an analysis of the percent of runners qualifying at certain races and following through with applications to Boston. Boston had one of the highest rates – around 40%.
Second, the weather at the 2024 Boston Marathon was unseasonably warm. It wasn’t terrible, but it was bad enough that many runners had very bad days. The number of runners with large positive splits and/or DNFs was a lot higher than usual.
As a result, the number of runners meeting their own qualifying times was atypically low.
In 2023, 13,410 finishers at the Boston Marathon met their qualifying times – out of approximately 23,000 runners who entered via time qualification.
In 2024, only 9,538 finishers at the Boston Marathon met their qualifying times – out of approximately 22,000 runners who entered via time qualification.
The number of qualifiers dropped by almost 4,000.
So at first glance: Yes. The results of the 2024 Boston Marathon would appear to pave the way for a weak qualifying field for the 2025 Boston Marathon.
What About Other Races?
Despite it’s size, the Boston Marathon is still only one race. It yields a lot of qualifiers – but in a good year it still only yields around 5,000 to 6,000 applicants to the next year’s race.
In 2024, there were over 30,000 applicants. So there are a lot of other races that matter.
The dataset I based my original analysis on included around 250 races in each of the two qualifying periods. Across the board, many of those races saw a) larger fields and b) larger numbers of qualifiers.
The biggest increase came at the Chicago Marathon – where the number of qualifiers increased from 6,035 to 9,379. Joe’s analysis also shows that runners at Chicago convert at a rate of around 30%. By itself, the increase at Chicago for much of the decrease seen at Boston.
As you go down the list, the top twenty races with additional qualifiers yielded a total of almost 9,000 additional qualifiers compared to the 2024 qualifying period. That initial dataset did not include the Berlin Marathon, which also saw an increase of around 1,700 qualifiers.
When you look across the entire dataset, which I’ve updated to include the last chance races from early September, there were:
- 51,779 qualifiers in the 2024 qualifying period
- 56,926 qualifiers in the 2025 qualifying period
That’s a net increase of 5,147 qualifiers.
The number of qualifiers dropped by close to 4,000 at Boston and 3,500 at London, because the 2024 qualifying period included both the 2023 and 2022 London Marathons. But the number of qualifiers across the rest of the field increased so much that this 7,500 qualifier deficit was erased – and an additional 5,000 qualifiers were added to the field.
But Boston Runners Matter More Than Other Runners!
There’s nothing new in the data above that I haven’t already described in my previous analyses.
But in thinking about this topic, I did come up with a new question to explore. What happens to those Boston Marathon runners who failed to re-qualify in Boston 2024?
As the argument goes, runners at Boston are very likely to apply for the next year if they qualify. But if they don’t qualify, they won’t apply.
But while I was out for a run, I realized something. Just because these runners didn’t qualify at Boston doesn’t mean they didn’t qualify at all.
It’s also true that many runners who qualify for Boston run multiple marathons per year. Two is a fairly typical number, and some people will run three or four. There’s a good chance that these runners had already run a fall race, and there was also plenty of time for them to run a late summer or early fall race after Boston.
So these failed qualifiers will fall into three buckets. Either they:
- Ran a fall marathon and already had a qualifying time in April 2024
- Ran a race after Boston and achieved a qualifying time later in 2024
- Didn’t qualify at all
I decided to look at the data again to see if I could quantify how many failed qualifiers fit into these three buckets.
How Many Failed Qualifiers Were There?
Let’s start with the basic question. How many failed qualifiers were there, and who were they?
We know that accepted applicants into the 2024 Boston Marathon beat a 5:29 cut-off score in order to gain entry. So these runners are not just capable of BQ’ing, they’re capable of dipping quite a bit under their qualifying time.
It’s normal for people to run a few minutes slower at Boston due to the difficulty of the course. But despite that, in good conditions most of these runners would at least be able to notch a base qualifying time.
On the flip side of the field, there are plenty of charity runners who might run 20, 30, 40 or more minutes over their qualifying times. These people never really had a chance to qualify, anyway.
What we’re looking for is the group that is slightly over their qualifying time – and this should represent the people that would have otherwise been in a good position to qualify in a normal year.
I played around with different cut scores, and I settled on a cut-off of BQ + 10 minutes.
This gave me a group of 3,469 finishers at the Boston Marathon who finished within 10 minutes of their Boston qualifying time. That’s close to the drop in qualifiers between the 2023 and 2024 Boston Marathons, so I think that’s a good group to start with.
How Many Of Them Qualified At Other Marathons?
Next, we get to the trickier part. If we can match the results for these runners at the Boston Marathon with results for the same runners at other marathons, we can see how many of them qualified at other races.
The best way to do this match on a large scale is to simplify the runner’s names, to eliminate differences in formatting, and look for a match between name, gender, and age. You also need to account for the fact that a runner could age up partway through the year – so their age at Boston might be a year higher or lower than their age at another race.
I took my sample, and I narrowed it down to the results for runners who ran a qualifying time in the 2025 qualifying period at a race other than Boston. I eliminated duplicates, and I kept the fastest time for each runner.
Then, I matched this against the results for the 3,469 failed qualifiers at the 2024 Boston Marathon.
The results?
A total of 1,358 of the failed qualifiers matched to a qualifying result at another race. 1,090 of them came before April 1, and 268 of them came after April 1.
This method isn’t perfect, and it could easily miss some positive matches. It’s also possible that it picks up some false positives – multiple people of the same age, gender, and name.
But it should be largely accurate, and even if the number isn’t precise – the magnitude is. More than a third of these runners likely qualified for Boston 2025 at another race between September 1, 2023, and September 13, 2024.
So the number of finishers at the 2024 Boston who didn’t qualify for the 2025 Boston Marathon is actually significantly lower than 4,000.
Where Did They Qualify?
I was interested to see the distribution of where these people ran.
Here’s a graph with the top ten races from before April 1, 2024.
Berlin and New York also each had about 100 qualifiers. After CIM and Philly, the numbers dwindle to a handful per race.
But these are all popular races that a frequent marathoner might run in the fall. And it’s quite plausible that they had already picked up a BQ at one of these races before they got to the start line of Boston 2024.
What about afterwards? Here are the top ten races after April 1.
It surprised me that London was at the top of the list. The 2024 London Marathon was only a week after the 2024 Boston Marathon, so these runners would have had to turn around and race again only a week later.
But it’s certainly possible. Last year, CJ Albertson ran CIM in 2:11:09 and followed that up with a 2:11:30 the following weekend at the Baja California Marathon.
Granted, these guys aren’t that elite. But they’re fast. And if they jogged it in at Boston – either by design or due to the weather – it’s quite possible they turned around a fast time a week later on a fast course. And given the large numbers involved, it’s not crazy that at least someone did this.
Nonetheless, I manually checked some of the names to make sure it wasn’t a fluke in the data. It’s hard to say for certain, but some of these guys – with names like Schlueter, Khachadourian, and Cebotari – are almost definitely valid matches.
I expected to see many of these other races on the list, though. Erie is a popular last chance qualifier, and I’m sure some of these runners marked it on their calendar as soon as they failed at Boston. Many of the others are downhill marathons, and they’re quite common targets for people who want to be sure that they BQ.
Now You Know the Rest of the Story
As Paul Harvey would say, now you now … the rest of the story.
Yes, the 2024 Boston Marathon was unseasonably warm. Yes, there were fewer qualifiers at that race than normal.
But the ledger was more than balanced out by an increase in the field size and the number of qualifiers out of races like Chicago – and many others.
And when you look deeper at the finishers in Boston, a large percentage of the runners who failed to qualify did run a qualifying performance at another race. Many of these runners compete in two or more marathons per year, so a single bad performance – either because of weather or because they had a bad day – doesn’t mean that they won’t qualify.
That’s the danger of fixating on one data point and neglecting the big picture. The results of one marathon, taken in isolation, can’t tell you everything you need to know. You need to look at the aggregate results of all the races – or at least many of them – to get a good picture of what’s going on.
And what’s going on is that there are way more qualifiers out there this year – and that will likely result in a qualified applicant pool that is larger than last year’s.
But we’ll find out (hopefully) tomorrow when registration ends.