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5K distance variation (Read 1825 times)


I've got a fever...

    Also, as far as a 2% error for uncertified courses, this is bullocks.
    I believe that if it were somehow possible to determine the confidence interval about the mean distance for all certified courses versus all uncertified courses, the value would be larger for uncertified courses. Or to out another way; if you compared certified vs. uncertified courses, I believe you'd see p<0.01>0.01, maybe even 0.05. Who knows. I usually just run the course, and trust the results unless I reason to believe otherwise.</0.01>

    On your deathbed, you won't wish that you'd spent more time at the office.  But you will wish that you'd spent more time running.  Because if you had, you wouldn't be on your deathbed.


    A Saucy Wench

      Also, as far as a 2% error for uncertified courses, this is bullocks. Basic statistics, folks. Here is the deal: All courses are either the correct distance or they are not. Courses that are not the correct distance have an error. There is no reason to believe that a course with an error has a higher degree of error just because it was or was not certified. A statement that is more likely correct is this: There is a 1% chance that a certified course is the incorrect distance while there is a 5% chance that an uncertified course is the incorrect distance. (these are, of course, funny numbers to provide an example) Also, please remember that there are several steps to getting the correct distance - - measurement, in which the course is measured by a standard method* - layout, in which the race director and team sets up the course correctly along the measured course - race, in which the runners actually follow the measured route along the measurement line. *this is where certification comes in
      Yes and no. I get what you are saying that you are merely reducing the likelihood of error, but I contend that a significant number of uncertified courses also use measuring techniques that introduce a greater AMOUNT of error as well. I cant remember what the specific accuracy of each measurement device is as it has been years since I looked it up. Not all that many "community" races even use a wheel to measure. I've seen them use a car odometer (horrendous accuracy), a bike odometer (still shockingly piss poor), GPS ('nuff said) and even gmaps. In those cases not only is the likelihood of error higher, the magnitude of error will also be higher. I also think there are good organizations who simply are not going to pay USTAF for certification but follow all of the practices themselves. Personally I dont see much reason to worry about it either way. I will sometimes compare top finisher times as Jim does, but not to see if a course is "long" or "short" but to see if my relative performance vs. another race was a factor of overall course difficulty

      I have become Death, the destroyer of electronic gadgets

       

      "When I got too tired to run anymore I just pretended I wasnt tired and kept running anyway" - dd, age 7


      A Dance with Monkeys

        Globbie and Ennay are essentially saying the same thing, that uncertified courses' measurement technique is less likely to be accurate than one that has been measured as part of a certification process. A fine hypothesis. How do you plan to test the hypothesis?
          This is one of the best GPS accuracy references I've seen yet. Excellent information.
          You guys do suck - you knew an engineer would fall for that!


          I've got a fever...

            A fine hypothesis. How do you plan to test the hypothesis?
            Since I don't have a lot of time on my hands, my test will most likely consist of a six pack of Sierra Nevada pale ale and use of the Chewbacca defense.

            On your deathbed, you won't wish that you'd spent more time at the office.  But you will wish that you'd spent more time running.  Because if you had, you wouldn't be on your deathbed.


            A Saucy Wench

              Globbie and Ennay are essentially saying the same thing, that uncertified courses' measurement technique is less likely to be accurate than one that has been measured as part of a certification process. A fine hypothesis. How do you plan to test the hypothesis?
              I believe both of us followed it up with something along the lines of Dilligaf.

              I have become Death, the destroyer of electronic gadgets

               

              "When I got too tired to run anymore I just pretended I wasnt tired and kept running anyway" - dd, age 7

              JimR


                GPS error
                This is one of the best GPS accuracy references I've seen yet. Excellent information.
                Agreed. I've already bookmarked it for future reference.
                  You guys do suck - you knew an engineer would fall for that!
                  True.

                  2013 Goal: Make 3:00:16 go away - FAIL.

                  2014 Goal: Make 3:00:16 go away.

                    Yes and no. ... Not all that many "community" races even use a wheel to measure. I've seen them use a car odometer (horrendous accuracy), a bike odometer (still shockingly piss poor), GPS ('nuff said) and even gmaps. In those cases not only is the likelihood of error higher, the magnitude of error will also be higher. I also think there are good organizations who simply are not going to pay USTAF for certification but follow all of the practices themselves. Personally I dont see much reason to worry about it either way. I will sometimes compare top finisher times as Jim does, but not to see if a course is "long" or "short" but to see if my relative performance vs. another race was a factor of overall course difficulty
                    My personal favorite was one run in a city park where the organizer just added up the numbers on the park map for the different trails the course followed, and juggled it around until it hit 5K. I ran a 17:34 or something like that when I should have been around 18:15 on a flat course, and this definitely wasn't. I think the course was about 4.75km, or that's what the results went on the website as, and maybe shorter than that. I'm actually surprised it ended up being that close.

                    2013 Goal: Make 3:00:16 go away - FAIL.

                    2014 Goal: Make 3:00:16 go away.


                    Feeling the growl again

                      I have heard of the following being used to measure uncertified courses: 1) Car odometers 2) Bikes 3) Pedometers 4) Wheels 5) GPS 6) Online mapping 7) How long it took the RD to walk it! 8) A guess. Seriously! All were advertised as a specific distance with no disclaimer as to the lack of care put into course measurement. This is a case where even the scientist in me does not require a Student's t-test to be confident that uncertified courses are further off than certified courses (or more likely to be as well). The only times I have heard of certified courses having significant issues is when the course is certified but then they do not use the course (move a start or finish line, or the roads the course run on change due to construction and alter the path).

                      "If you want to be a bad a$s, then do what a bad a$s does.  There's your pep talk for today.  Go Run." -- Slo_Hand

                       


                      I fly.

                        I ran a certified 5k last month only I know that the course was not the length certified. 2 miles of the course were on bridges and the bridges that were used for the certification are being torn down and replaced. So the course was actually a bit shorter than a 5k. Not much, but enough so that the certification (IMO) should no longer count.

                        Bring it on.


                        I've got a fever...

                          I ran a certified 5k last month only I know that the course was not the length certified. 2 miles of the course were on bridges and the bridges that were used for the certification are being torn down and replaced. So the course was actually a bit shorter than a 5k. Not much, but enough so that the certification (IMO) should no longer count.
                          The certification would lapse if it were a USATF-sanctioned event. The RD for your event didn't want to go through the trouble or expense of having the course re-certified. Even re-paving the roads would require a re-cert, as the tangent lines will often change (i.e. if curbs are in slightly different positions, etc.)

                          On your deathbed, you won't wish that you'd spent more time at the office.  But you will wish that you'd spent more time running.  Because if you had, you wouldn't be on your deathbed.


                          I fly.

                            The certification would lapse if it were a USATF-sanctioned event. The RD for your event didn't want to go through the trouble or expense of having the course re-certified. Even re-paving the roads would require a re-cert, as the tangent lines will often change (i.e. if curbs are in slightly different positions, etc.)
                            I guess it wasn't a sanctioned event. I just know that they advertised it as certified and so I looked up the course online before the race. Since I drive over the new bridge and the old bridge was referenced I knew to expect a slightly different length event. And since I'm not all that fast and it was only a 5k, which I was running for fun, I didn't worry about it.

                            Bring it on.


                            A Dance with Monkeys

                              My personal favorite was one run in a city park where the organizer just added up the numbers on the park map for the different trails the course followed, and juggled it around until it hit 5K.
                              Heh. I know a marathon like that...


                              HobbyJogger & HobbyRacer

                                All courses are either the correct distance or they are not.
                                Well, when you get to the quantum level, wouldn't it be more accurate to say that courses have different statistical spreads -- a course doesn't have a distance, it has a statistical spread of likelihood of distances? MTA: Much like a marathon doesn't have a specific number of monkeys, it has some statistical distribution of monkeys -- it may be very likely to have no monkeys, and less likely to have one monkey, and so forth -- and perhaps some other race is very likely to have a herd of about 200 monkeys...

                                It's a 5k. It hurt like hell...then I tried to pick it up. The end.

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