The Slow Motion Argument: Old and Getting Older

Commentary by Ted Wagner

In 1994 the IPC Formation Skydiving Subcommittee took the bold step of changing the competition rules to make real-time electronic judging possible.  Computers, in the form of TRUSCORE (by our friends at Larsen & Brusgaard) and OmniSkore!, now perform highly accurate working time collation, score calculations, and more.

One important element of the new rules was the elimination of judging with the use of slow motion.  There were two main reasons why this was done:

Currently there are only two guaranteed speeds on commercial video equipment: "Play" (100% speed) and "Stop" (0% speed).  I know of no consumer VCR equipment which offers an intermediate playback speed at a known (much less guaranteed) frame-rate.

There is one potential solution for this, however: using computer-digitized video.   Software can guarantee the playback of the video at a precise frame rate (e.g., 25 fields per second for a half-speed playback of PAL video).  This technology is now available but not yet affordable for most organizers.

But that's technical stuff.  Shouldn't the competitor's needs come first?

Of course.  The integrity of the competition should always be a primary concern.   But I submit that using slow motion is not only unnecessary to achieve fair judging, it can be detrimental.

Let me start out with a quick look at some other popular sports.  Here's a short list of events which are officiated in real-time without the benefit of any second look:

And here are some where the officials are allowed a second look, but without slow motion:

Finally, here's a list of popular sports where slow-motion video is available for judging:

(That's right.  There aren't any.)

Note that America's National Football League experimented with "instant replay" at one time.  Not only did it prove to be unmanageable and time-consuming, but it degraded the authority and credibility of the officials on the field.  The NFL punted on the experiment after just two seasons and no one has missed it since.

Of course, we shouldn't get too distracted by what other sports are doing or not doing.   We should set the competition rules for our sport that are the best for it.

So, cutting to the chase: the real reason not to use slow motion judging for Formation Skydiving is that it doesn't improve the quality of judging or the accuracy of the results.  Wait!  I can explain.  I'll use my favorite analogy, familiar to anyone who has studied fractal geometry.

How long is the coastline of England?

There.  It's that simple.

Given a scale map of England that fills a piece of A4 paper, it is not hard to trace the island's outline and multiply the length of the trace by the map scale to get the answer.

But wait!  Someone questions the accuracy of your answer because of the map's limited detail.  So you repeat the exercise with a wall-sized map which, as you know, has more coastline detail.  But this time you get a very different answer. 

I'm sure you see where my example is taking you.  "Zooming" into the coastline may provide a glimpse of a fjord or an inlet that you couldn't see before, but now there is more information to process, which changes your answer to the problem.   (The point of this example in fractal geometry is to illustrate that the closer you examine the problem, the greater the variance in the answer.)

Of course, there is not the explosion of detail in "zooming in" (slowing down) the playback of a skydive.  However, you get a similar result: for every question that is answered by a slow-motion viewing, another question is raised.

Example: A judge sees a skydive in normal speed and says "Hmm... I'm not too sure about the separation from 4 to 5.  Slow motion please."  The tape is replayed at 50% speed.  Now the judge says "Okay, the separation from 4 to 5 is okay, but now I'm not sure they correctly built the 14th formation."  So the tape is replayed at 25% speed.  Now the judge says "Okay, I got an answer on 14, but now I see something on 12.  Slower please."  So the tape is replayed at 12.5% speed.  Now the judge says "Gosh... 4 to 5 really was dirty.   I called it right the first time...".  Pretty soon the tape is being played one frame at a time.  Finally, when it's all said and done (and a long time later), the judge records the results of his first viewing.

This example accurately describes my experience with judging with slow motion.   Invariably, the good judges made their best call the first time.  (Which, BTW, was the NFL's experience...)

Judging Competence is Everything

Nobody is saying that real-time, normal-speed judging is easy.  It isn't.  It takes practice -- lots of it.  But slow motion should not ever be used as a remedial solution for lack of judging expertise.  Judges must know the dive pool in intimate detail and learn how to "call it the way they see it and stick to the way they call it."  Yes, they will miss a call here and there, just like baseball umpires who let that bad pitch fall in the strike zone once in a while.  But our sport will be better off for it.

-Ted Wagner (seconded by Tim)