Over 5000 Disqualified From The Mexico City Marathon

An unprecedented number of runners have been disqualified from The Mexico City Marathon. Did they all cheat, or were some victims of timing errors? After I posted an article...

An unprecedented number of runners have been disqualified from The Mexico City Marathon. Did they all cheat, or were some victims of timing errors?

After I posted an article regarding the accusations that 1000s cheated at the Mexico City Marathon, the race released the official results. According to the race website 5,806 runners were disqualified.

I did not pull the preliminary results immediately following the race, so my #s differ slightly from the #s the race published.

From the Mexico City Marathon website:

Total athletes who crossed the finish line 28,206

Total athletes who completed the full course (Finishers) 23,887

Disqualified 5,806

The # disqualified does not equal the difference between total athletes that crossed the finish line and those listed as finishers.


The data I had pulled show the following:

5,553 runners were removed from the results

1,570 runners were added to the results


Missed Splits – Full Field

Total Runners                 27,873 100% 23887 100%
Missed 0 mats                 17,827 64.0% 19376 81.1%
Missed 1 mat                   3,502 12.6% 3497 14.6%
Missd 2 mats                   1,435 5.1% 1012 4.2%
Missed 3 mats                   1,381 5.0% 2 0.0%
Missed 4 mats                   1,006 3.6% 0 0.0%
Missed 5 mats                       766 2.7% 0 0.0%
Missed 6 mats                       946 3.4% 0 0.0%
Missed 7 mats                       719 2.6% 0 0.0%
Missed 8 mats                       291 1.0% 0 0.0%


You can see from this data that they disqualified practically every runner that missed 3 or more mats.


Total Runners % of Field Total Runners % of Field
missed  3.1 4978 18% 465 1.9%
missed 6.2 4418 16% 47 0.2%
missed 9.3 5659 20% 1061 4.4%
missed 13.1 4018 14% 284 1.2%
missed 15.5 4323 16% 870 3.6%
missed 18.6 2722 10% 313 1.3%
missed 21.7 4179 15% 2133 8.9%
missed 24.8 1109 4% 354 1.5%

I did a quick analysis of the remaining runners – I checked for large negative splits, and pace variances following missing splits, and it appears that there are still well over 100 runners with questionable results.

There is more analysis to do in order to analyze for timing mat issues (more on that later).

Missed Splits – Boston Qualifiers

Total Runners 1296 100% 495 100.0%
Missed 0 mats                       397 30.6% 398 80.4%
Missed 1 mat                         89 6.9% 87 17.6%
Missd 2 mats                         58 4.5% 9 1.8%
Missed 3 mats                       171 13.2% 1 0.2%
Missed 4 mats                       147 11.3% 0 0.0%
Missed 5 mats                       132 10.2% 0 0.0%
Missed 6 mats                       167 12.9% 0 0.0%
Missed 7 mats                       106 8.2% 0 0.0%
Missed 8 mats                         29 2.2% 0 0.0%
Total Runners % of Field Total Runners % of Field
missed  3.1 658 51% 30 6.1%
missed 6.2 627 48% 1 0.2%
missed 9.3 761 59% 20 4.0%
missed 13.1 623 48% 2 0.4%
missed 15.5 574 44% 7 1.4%
missed 18.6 351 27% 2 0.4%
missed 21.7 292 23% 43 8.7%
missed 24.8 56 4% 3 0.6%

After the disqualifications, the # of Boston qualifiers went from 1296 to 495. There are still a handful of Boston qualifiers whose results are questionable.

I am also looking closely at the results to try to find an explanation for the 21.7 mile mat data. It doesn’t appear that any of the runners that only missed that mat gained any advantage over the portion of the course where they missed the split.

Some Official Results are Still Questionable

As shown in the data above, The Mexico City Marathon basically removed runners that missed 3 or more splits (with a few exceptions). Also, it is unclear on what happened with the runners that were added to the results. I did see some comments on the initial article that a runner reported that their finish time was not recorded initially. This may be a correction to an issue at the finish line.


Some of these results could potentially be justified. Most of the truly suspicious results come from runners that missed that didn’t register a time at the 10k timing mat (6.2 mi). Also, it is interesting that some of these runners have identical gun and chip times. In order for those times to be accurate, they would have had to start next to the elites. But, the runners that are showing 2 minute paces cannot have those times explained by faulty timing mats. Regardless of whether they intentionally cut this portion of the course, these official splits cannot be accurate.

In the original race results, over 4000 runners had identical chip and gun times. All but 500 of those runners were disqualified. It is physically impossible that 4000+ runners were all crossed the timing mat at the same instant. Typically this would indicate that no start time was registered for those participants.

Also, ‘Maria’ is still in the official results results.

Timing Issues or Cheating?

I still have a difficult time with accepting that 5800 runners cut the course (deliberately or otherwise). I, along with others whose help I have solicited, are continuing to analyze the data. We are looking deeper into the mats that were missed to see if there is a pattern.

It is possible that the timing system was not sufficient for the # of runners that were crossing the mats. If you have a non-redundant system, and more runners cross the mat than the system is equipped to handle, you can have runners whose data is not collected. For this, and similar circumstances, I am not necessarily concerned when a runner misses 1 or 2 mats, if they don’t show any pace improvement over that stretch of the course. However when a single runner misses multiple mats – it becomes more unlikely that they just happened to be victimized by an overwhelmed system every time.

The initial pace analysis showed a significant amount of results that could not be explained by timing error. More analysis is needed to try to determine how many of the 5800 runners actually cut the course (intentionally or unintentionally) and how many (if any) were victimized by a potentially overwhelmed timing system. By disqualifying the runners from the official results, the race is in essence saying that those runners cut the course.

To put this in perspective, I wrote about widespread cheating at Honolulu and Disney. I estimated those races had 400 and 200 course cutters respectively.

More updates will come as the data is analyzed further.




Please consider a contribution to help support the site. Contributions help to offset costs associated with running the site and help to enable me to compensate those that assist in data collection, etc.

Thanks to all of you that that support Marathon Investigation!


One Time Contribution


Mexico City Marathon
10 Comments on this post.
  • Florian
    15 September 2017 at 4:54 pm

    Hi Derek. Thanks for the update!

    As I commented on your original article, I observed the race at KM 34 until about when the 4:15h runners came through. From what I saw, I fully believe the number of 5800 course cutters.

    It was very irritating, and I thought maybe there was a half marathon started in parallel. Only when I saw the Facebook pages that denounced the cheaters did I start to understand what had happened. I actually remember observing a similar situation at the same run 3 years ago. It’s not the first time this has happened.

  • Sebastian
    15 September 2017 at 6:48 pm

    Interesting analysis. Where did you get the raw data?

  • Robert F
    16 September 2017 at 1:52 pm

    I’d like to hear from some of the people who were disqualified. I’d bet that the vast majority of them didn’t intend to “cheat”. I just can’t imagine 5,000 people signing up and paying their entry fee with bad intent.

  • Chris
    16 September 2017 at 2:18 pm

    I appreciate the work you’re doing, Derek, as many others do I’m sure.

    Can you add where the results can be downloaded or viewed? I’m interested to see some of this data myself.


  • Larossa
    16 September 2017 at 5:45 pm

    Maria is looking sexy! UGH!

    Thanks, Derek, again for all your work on this. Bringing this to light, helped steer the RDs to doing the right thing.

  • Larissa
    16 September 2017 at 5:50 pm

    I wanted to add, if they are DQ’d and want to fight it, they can always show proof, via photos and running watch w/ splits. Some may not have watches, but photos can help provide proof based on the photos’ time stamps.

  • Pedro
    17 September 2017 at 2:48 pm

    Cheating is a strong word. I can’t talk for everybody but myself.
    After running the 2016 edition of this marathon I wanted to repeat the experience and I paid for the entry fee last year to run the 2017 edition. Later on the year, I decided that I wanted to do an international marathon so I applied for the Chicago marathon and I got a place through the lottery. I am not an experienced runner and I thought that it was too much for me to run two marathons in +30 days, so I decided to focus on the Chicago one. At first, I just wasn’t going to run the Mexico Marathon, but then a friend convinced me to use it as a training, and so I did. I ran 32k that day. I never said I ran the full 2017 Marathon or posted everywhere a picture of myself at the finish line, I just took advantage of a place in an organized race to do a long distance training, but of course, I am among those +5000 disqualified runners (which is fair) because I didn’t cover the entire distance.
    Is that cheating?, I let you decide.

    • Mike Rossi’s 6 hour Ironman
      17 September 2017 at 6:21 pm

      You’re right – not everyone cheated and I’m sure there are other stories such as yours. That said, if there are excessive missed timing mats, there should be massive DQs. A DQ doesn’t mean you cheated, but you should never benefit from such an issue. Good luck in Chicago.

    • Brian
      20 September 2017 at 9:10 am

      Pedro, if you started the race and then dropped out early, thereby using Mexico City as a training opportunity, I would not say you cheated. If you jumped in after the start and ran to the finish, you are a cheater. In fact, if you crossed the finish line at all and did not run from the start to the finish, you are a cheater.

  • Scoreboard
    17 September 2017 at 3:04 pm

    Personally I’m impressed they so swiftly DQ’d as many highly questionable entries as they did. I figured it would take some substantial time and work to convince they to disallow those results, but they acted relatively quickly once it came to light.