# Prediction Time – What Will It Take To Make The DI Championships?

February 09th, 2017

Jacob Skipper is the swimming SID at William & Mary.  He stays away from the water.

Now that conference season is upon us, one of the questions that preys upon everyone’s mind is what will it take to get in?  Below are my semi-educated guesses, along with the rationale I used to arrive at them.  This is a tool I’ve come up for my own use the last couple years, so that I can try and have a heads-up when an athlete is nearing NCAA qualification.

The Method

I took the last several years of final-invited times off the NCAA psych sheets, dating back to 2011, and calculate the year-by-year change.  Then, I use a simple formula to average all of those changes, with an extra weight to both the most recent year-change, and the year-change to the equivalent earlier year, and add that to last year’s invited time. So, for 2017, I weight the change between 2015 and 2016, as well as the change between 2012 and 2013 (the most recent year after an Olympics year).  The excel formula is average((2*mostrecent),(2*mostsimilar), N1, N2, N3, etc…), where the Ns are the other years changes (in this case, 11 to 12, 13 to 14, and 14 to 15).  The double-weight to the most recent year is a change for this season.  Also new to this year is a weight to try and correct for the error I found from last year’s predictions.  In the example:  I had projected last year’s men’s 500 free to need 4:17.01 to qualify, and the last invited was 4:17.73.  Dividing the actual by the projected gives an error of 1.002817055.  This year, once I had done the original calculation, I then multiplied it by the error factor to achieve the refined projection.

Assumptions

– Only looking at the individual swimming events.  The relays are now entirely dependent on the individual qualifications, so it’s not useful to figure out the time you need to go – it’s conceivable that a school could set the world record in (say) the 200 medley relay, but not swim at NCAAs because no one qualified individually.

– Similarly, didn’t look at the diving events.  Once you meet the regional standard, it’s entirely dependent on the competition at the zone meets.

– I only looked at the official psych sheets cut line for each year.  If there was a late-add alternate, they don’t figure in.

Disclaimer

I am in no way affiliated with the selection committee, nor am I psychic (that I’m aware of).  These are predictions and guesses, informed only by my knowledge of numbers and 10-year experience as a collegiate SID.  If you rely on these numbers, and you or your swimmer misses out on the NCAA Championships because you thought you/they were safely in and the cutoff came in lower, that’s your own mistake.

The Numbers

With no further ado, here is the table of projections.

 Men’s Time Event Women’s Time 4:18.31 500 Free 4:42.37 1:44.24 200 IM 1:57.67 19.54 50 Free 22.30 3:45.88 400 IM 4:09.79 46.30 100 Fly 52.75 1:34.80 200 Free 1:45.73 52.87 100 Breast 1:00.58 46.56 100 Back 52.89 15:01.02 1650 Free 16:17.92 1:41.80 200 Back 1:54.28 43.16 100 Free 48.65 1:55.58 200 Breast 2:10.55 1:43.56 200 Fly 1:57.07

Here is a simplified source table – the columns are what I projected for last year, what it actually took, what the absolute (in seconds) and percentage error (absolute error divided by the actual invite).  Negative numbers in the error denote that I projected a slower time than it actually took to make the meet.

 Event 2016 Projected 2016 Actual Absolute Error Pct. Error Men’s 500 Free 4:17.01 4:17.73 0.72 0.28% Men’s 200 IM 1:44.37 1:44.41 0.04 0.04% Men’s 50 Free 19.50 19.53 0.03 0.15% Men’s 400 IM 3:44.85 3:45.61 0.76 0.34% Men’s 100 Fly 46.49 46.44 -0.05 -0.11% Men’s 200 Free 1:34.43 1:34.67 0.24 0.26% Men’s 100 Breast 52.88 52.92 0.04 0.07% Men’s 100 Back 46.35 46.51 0.16 0.34% Men’s 1650 Free 14:58.24 15:00.11 1.87 0.21% Men’s 200 Back 1:41.65 1:41.92 0.27 0.26% Men’s 100 Free 42.93 43.05 0.12 0.28% Men’s 200 Breast 1:54.92 1:55.31 0.39 0.34% Men’s 200 Fly 1:43.49 1:43.65 0.16 0.16% Men’s Error Average 0.20% Women’s 500 Free 4:43.08 4:42.69 -0.39 -0.14% Women’s 200 IM 1:57.90 1:57.90 0.00 0.00% Women’s 50 Free 22.35 22.35 0.00 -0.02% Women’s 400 IM 4:12.01 4:11.05 -0.96 -0.38% Women’s 100 Fly 52.74 52.77 0.03 0.06% Women’s 200 Free 1:45.80 1:45.84 0.04 0.04% Women’s 100 Breast 1:00.70 1:00.66 -0.04 -0.07% Women’s 100 Back 52.96 52.93 -0.03 -0.05% Women’s 1650 Free 16:17.70 16:17.64 -0.06 -0.01% Women’s 200 Back 1:54.32 1:54.47 0.15 0.13% Women’s 100 Free 48.84 48.77 -0.07 -0.14% Women’s 200 Breast 2:11.11 2:10.89 -0.22 -0.17% Women’s 200 Fly 1:56.93 1:57.02 0.09 0.08% Women’s Error Average -0.05%

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Louisiana Swimmer

What is a swimming SID?

completelyconquered

It’s the Sports Information Director. They are the people that will collect media and put together media for athletics at universities.

barbotus

Sports Information Director

coacherik

Sports Information Director.. Based on this report, one who actually takes the time to get to know the sport he is responsible for. Thank you!

dmswim

This is awesome! Thanks!

Is it true that if a school posts an A relay standard, those athletes can compete in that and any other relay?

So the only way a swimmer can get to the meet is by qualifying individually? Relays are not invited? Please clarify. Thanks!

Coach Hannah

Relay only swimmers are selected by the coach, and they would attend the meet to swim in only the relays the team needs them in.
To swim individually, you must qualify individually.
To swim on a relay, you must be an individual qualifier OR one of the four relay only swimmers the team takes to the meet.

Jacob Skipper

If a school gets 1-3 swimmers invited, then they can swim any relay that they have “A” cut for. If they have 4+ swimmers invited, then they can swim any relay that they have “B” cut for. That’s the only way you get to swim relays now. If the team wants to, they can bring up to four swimmers who will only swim the relays (on the school’s dime, vs. the NCAA who pays for all the actual invited people). Those relay-swimmers CANNOT swim any individual events.