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Automatically flag blatantly impossible things

There are a significant amount of activities that have what I will call impossible results. There are quite a few reasons why this could happen, including bad GPS data, wrong activity type, using a car, etc. Strava should implement some checks to automatically flag blatantly impossible things that are well beyond the capabilities of human performance like sub 3 minute running miles, or tens of thousands of feet of gain in an hour long run.

The leaderboards of the monthly running climbing challenges are frequently garbage results from random athletes whose watches recorded crazy elevation gains on what are almost always completely flat runs. It would be easy to check their VAM against known world best performances and see that such gain is literally 10 times more than the world's best mountain runners could do in that time period. Or simply do a GPS spot check against the altitude data that their watch recorded, often altitudes of over 20,000 ft (and they aren't in the Himalayas, Denali, or the Andes).

There are many similar threads to this, some that are quite old. I really don't know why Strava has not fixed this yet.

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  • Dan, go to your Settings page and change your Default Sport.

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  • Hi Dan

    On the Strava website, go to the Settings page, then click the Display Preferences menu item on the left. You'll be able to choose your default sport

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  • Thanks Phong!

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  • Over the years I have flagged literally 1000s of rides by motorbike riders.  Sadly Strava you are going to lose your supporters if you are too lazy to implement auto flag for obviously false rides/runs.  There are other apps out now that are very similar as well as Garmin.  I'm just sick of having to flag the same motorbike riders, with profile pics of their motos, for doing 100km/hr up a 4% slope.

    It's just lazy on your part Strava and I'm looking elsewhere now.

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  • As I post here last year, wonder if you have to flag in bike and run activities, like I do. And you find every day an senior heavy weight WR breaker!!!
    It’s not had to put under quarantine any activity that is faster than any WR, in 400m, 1km, 5..... even a marathon winner faster than the fastest Quenia runner.
    In the other hand, around here, the bike segments KOM are almost 100% in a semi tail! They had rode the activity, but 90km/h is not real and should be auto flagged to.

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  • Here’s a good example of Strava’s automatic flagging hard at work:

    https://www.strava.com/activities/259789356/segments/60032954846

    This segment is part of a 5k that’s run on an airport runway, but people evidently start Strava while on an actual airplane. Strava happily obliges, granting them a course record for “running” at a casual pace of 33s/mi.

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  • This is ridiculous. some really simple measures could cut vehicle activities... like riding over 100km/h on anything but downhill. Or accelerating from 0 to 60 in a few seconds. Or climbing 10% hills at 50km/h. Lol... Anything that requires over 2500w should raise an alert as those numbers are only hit for a few seconds by top pro track sprinters. I refuse to pay premium while that kind of filter isn't added.

    PLUS there's no flag button in the android app, only in computer website.

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  • Why does Strava claim to have an autoflag system when it clearly doesn't or have one that remotely works? I was just on a training trip in Mexico and many cycling segment KOMs were listed being done at 50-80+ miles and hour... Here's one of many, at 50 mph on a zero percent grade:

    https://www.strava.com/segments/19847682

    For a data company, it seems astonishing Strava is incapable of implementing simple algorithms to flag data like this. Without a an autoflag system, I'm certainly not going to spend my time doing Strava's work reporting these. Why encourage people to create, train for, compete at segments when the data is invalid. It's very sloppy.

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  • "

    Currently, we do have an auto-flag system in place. The system works to detect when an uploaded activity ranks 1st on any segment leaderboards by an amount considered unlikely (based on how many athletes have matched the segment, either 25% faster or 50% faster than the existing fastest time). 

    We would love to improve this system and make the auto-flagging more robust and accurate. We appreciate the feedback and will keep you all informed when development on this system is planned. "

     

    You clearly dont.

    There is  KOM on the course I ride that that apparantly was achieved by riding it at 135mph. Its been up there for a long time.  Second place is done by riding a 54mph. Looking at the speeds these people are riding other similar sections or downhill sections on the route, and their speeds are 4-15mph.

    With these speeds and times, they should of been flagged by your auto flag system you claim to have in place.

    Your either lying or its broke.

     

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  • Strava must have an army of people handling flaggings. They would really do themselves a favor by implementing a system that would dismiss flawed workouts before they get into their database.

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  • I think 99% of them are just folks that forgot to turn off the computer at the end of the ride. Surely it wouldn't be to hard for the software to detect something amiss when a user returns to the start and then suddenly starts generating 10x the wattage.

    Wouldn't have to auto-flag - could just be a message to the user when they submit "Hey, did you forget to turn off your computer..."

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  • I just spent a bit flagging the top 23 people (almost the whole first page) on a 1 mile segment who had logged <2 minute running miles either on a bike or in a car. Many of them since I created this thread. But I even ran into a limit after about 17 people "Flagging is temporarily disabled."

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  • this feature clearly doesn't work. there are a large group of people who regularly cycle the Abu Dhabi F1 circuit, record it as runs and are the top 50ish people on the segment for the lap. They have averaged 30+ kph around the lap. That is blatantly impossible for a run. They do it with such regularity that each person needs to be flagged multiple times to remove their rides from the leader board, meaning literally hundreds of flags need to be raised for what is clearly impossible.

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  • i'm really really bored of strava.. to the point i'm considering stopping using it. actually most cyclists here in vietnam laugh if i mention strava.. it's known as being trash because so many motorbikes are on it. nothing ever gets solved. This auto flag system seems to be only over 100km/hr - i guess as a guy's morning ride was flagged, but later in the day him hitting 80+ km/hr, destroying KOMs wasn't flagged.

     Every time i use strava i flag people, often from years ago. others have given up. never any feedback, thanks. many flags don;t even seem to register, or those rides are allowed. who knows.

    There's no way I'll renew now. all I can hope is a competitor will come and require cadence or something, as strava just don't care. Maybe they are hoping for publicity when motorbike racers die trying to get a kom?

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  • Please make an algorithm that calculates the runners fastest & average runs, age etc to determine if the segment result is realistic. Not many runners makes a 10k run under 30min (even 35min ) so an extra check should be done for these.

    Let other runners easy flag unrealistic segment results in an easy way.

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  • Having limits on abuse of flagging activities is one thing, but that only makes sense if the number of invalid activities is low enough that you can flag the ones affecting your segments without hitting those limits.

    You now have some algorithm for detecting dodgy data and auto-flagging new runs: why not apply it to older activity data? You don't need to do every activity, start with those that hold the top position of segments.

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  • Any news on getting the updates for this applied historically?  It would be a huge under taking to do this for every run I come across that looks way out.

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  • Hoping the new algorithm works. Local guy here rides scooter-sessions without marking them, when you do enough of those, will the algorithm still work?

    I now flagged one of his rides which he called scooter-training, hoping he will mark future rides.

    It still feels like cheating, people doing their best on segments and losing it because someone is in a vehicle or behind a vehicle... not fair. Not a fan of punishment, but maybe Strava could remove segment-registration after a certain number of - validated and correct - flagged rides (10 or 20).

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  • So it effectively, is not working.  Presumably rolled out in advance of making Leader Boards a subscription-only thing.  So a "ride" that took all 27 koms a guy has ever had, has been flagged. Maybe auto, maybe manual, not by me.  Yet still, 5 days later, all 27 koms, from a flagged ride, are still assigned to this driver. I opened a ticket, a few days ago, no response, ride is still shown as flagged, all koms still belong to him.
    https://www.strava.com/activities/3449029088

    And they want to encourage people to pay for this??!

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  • The algorithm for auto-flagging is not working... I have been flagged for nothing by strava...last time I decide to make a MTB training at race pace and strava think some segment are on a vehicule our e bike lol...thats stupid ..so I lost the kom and dont want to give it back to me ...so why using strava if its not working when you go fast and try to catch a kom ... dont think I will paid anymore for strava ..not worth it .

    http://www.strava.com/activities/3516906498

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  • I see an auto-flag algorithm has been added, which I why I've had two rides auto-flagged recently vs zero in the previous 7 years. The only thing that looks funny is the same descent with a downhill and tailwind. It isn't even a segment. I'm guessing it's flagged because the "strava watts" are >1,000W for 2 minutes which is beyond the ability of humans? But the problem is strava-watts and the algorithm. It was done on a bike while coasting!

    On both of these rides I got KOMs on climbing segments. The "trust me" option was immediately denied for both, so the only option was to fill out a support ticket. Any idea how long that will take?

    It shouldn't be that hard to write an algorithm that effectively weeds out impossible efforts. First you need to model it properly, and Strava's modeling is quite crude. On a descent you need to expect a low CdA from tucking, plus if there is a tailwind, that can make a huge difference!

    Until this gets fixed I guess I'm going to get flagged a lot, because there are many steep descents and often it is windy.

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  • So yesterday I received a notification that I'd lost a KOM on an obscure piece of gravel road, that I immediately recalled is in the midst of an off road motorcycle trail network.  So I look, and sure enough, the prior KOM of ~15 minutes had been smashed.  The new KOM? 2:50, with a HR just over 100.  So Strava, whatever you claim to have done on this issue is not only years overdue, but not even close to sufficient.  Just WTF are you doing with subscription fees?

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  • I noticed a segment the other week that had picked up a nearby run. The segment was entirely uphill, my run was downhill. Yet this was matched.

    I submitted a support request, at which point I was pushed towards here to create a feature request.

    How could this possibly be a feature request, not a big report?

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  • I've had to flag about ten motorbike riders since the autoflag is still failing to catch them.

    Strava it is not that hard.  Riding at 50km/hr up an 8% slope is not a bicycle.  Another hint would be the constant profile pics of them riding their motorbikes.

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  • Still plenty of KOMS held at over 50 mph. Here's Jorge, with three Strava rides ever:

    https://www.strava.com/segments/15380033?filter=overall

    Let's have one single blog by Strava to explain why an algorithm that catches this is so complicated and years late.

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  • A blog about this would be great, just to explain it.

    The algorithm doesn't work that well. The guy I mentioned earlier still does his scooter-pacing efforts and those aren't flagged, I flagged a couple of them (which I hate doing 😟).

    I understand the difficulty. The question is how much faster can you go given certain circumstances? To use 'the scooter pacing guy' as an example: when someone has a heartrate of 155 while riding 32kph for an hour and a half on a certain route, can that same person ride 45kph on that exact same route with the same or slightly higher (10bpm) heartrate? 

    I can post an analysis of me and my friends doing efforts at certain rates but that doesn't say anything about this guy. What it does say is that going almost 50% faster while adding less than 10% bpm is next to impossible. That's something Strava could check based on values in the community and with a certain bandwidth. So when an effort is outside of this  bandwidth the ride is flagged.

    Another solution could be community moderators, a collection of members who check rides (for free / for a free month of Strava a year). When a ride is suspect (high speed, multiple KOMs, outlier compared to other rides or a rider that's flagged often) this ride is sent to a number of moderators to check, when a certain percentage of these moderators think the ride should be flagged it's flagged. A little bit like Amazon Mechanical Turk.

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  • The algorithm isn't applied to old data AFAIK. But it's easy enough to flag them if you see them.

    It seems that most people are annoyed by autoflag's failure to catch violations. I have the opposite problem though, autoflags on rides that shouldn't be flagged! Surely I'm not the only one? It's particularly annoying because you aren't allowed to vouch for it, it must go to review... which in my case took over a month... and they deflagged one but not the other! Plus they never tell you *why* the ride was flagged. I assumed it was because of high speeds I achieved on a descent with a tailwind, but I tried snipping out those descents and it was still flagged. It's real obvious that the ride was done on a bike if you actually look at the file. Plus there is no way any of the segments look suspicious at all. They must be flagging other parts of the ride.

    The algorithm is really poor. It shouldn't be that hard to catch stuff that's impossible on a bike and avoid flagging rides that are possible. Of course you won't get all the violations, but they should err on the side of caution when flagging too... especially when a flag has to go to review.

    I would have been happy to pay for Strava, but this issue immediately came up and frankly I'm a bit pissed about it. I think a lot of my rides are going to get flagged.

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  • Strava has stated  that they are working hard to respond to users' issues, and this one is clearly a serious one for many users. I justrecently subscribed and am willing to give Strava the remainder of the year to get much better at filtering out the majority of joke times that are commonly showing up. I don't know or care too much about what's behind impossible activity results's: who cheating vs forgetting to stop recording, vs device glitches, but I can't understand why it's difficult to put in place some simple filtering algorithm that should be effective enough to weed out the vast number of the fragrantly impossible readings. I don't buy into the notion that Strava users should be called on expose efforts that are so obviously  impossible for any human being to achieve. 

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  • I have recently reached out to Strava to fix a few segments near me, it is clear people have been taking the bus and recording it as a run. Their response was it is a community moderated platform and they pasted the instructions of how to flag an activity. Why should we be now paying for leader boards that are complete nonsense?

    This is issue has been rampant for years, but now having to pay Strava to spend time flagging items which are obviously unrealistic is quite offensive. I'm sure Strava have some clever people working for you who can determine some criteria that will automatically flag an activity (all activities, not just new ones), people can't run over 40kph for 5km for example, or run 1 minute kilometres. Remove the easy ones first to make Strava useful, and even consider blocking repeat offenders.

    There are some great ideas in this forum as to how to approach this problem. It would be nice if there was some action taken.

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  • What's stopping progress, I think, is that strava thinks the more the merrier : allowing cars, motorbikes planes, buses etc is wrong, but it's engagement! Guys are using it! Woohoo!
    They don't seem to compute loss of profit. My membership expired two days ago and I haven't renewed. How many more? Enough?
    Here in viếtnam motorbike riders race with it. I seriously don't know if strava are waiting for publicity when a motorbike rider kills a kid while using the app. 22die on the road every day already (more going to/ in hospital).
    Amazing that we care about the app and community more than strava. Does it really need a competitor to force change?
    Disappointed with it, every mention

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