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Here’s a quick synopsis of the estimating small proportions

problem that you’re rightly pointing out (that may be helpful for Flanker): Predicting low base-rate events is one of the hardest problems in forecasting and statistics because the thing you're trying to predict happens so rarely. Only a tiny fraction of high school football players will ever be drafted into the NFL. Estimates vary by year, but it's well under 1% of high school players. That creates several challenges. 1. Most predictions should be "no" Suppose 100,000 high school players exist and 200 eventually get drafted. Drafted: 200 (0.2%) Not drafted: 99,800 (99.8%) A model that predicts "not drafted" for everyone would be 99.8% accurate. This is called the accuracy paradox: a model can appear highly accurate while being completely useless for identifying the rare outcome. 2. False positives dominate Even a very good predictor can generate many more false positives than true positives. Imagine a scouting model that: Correctly identifies 80% of future NFL draftees Incorrectly flags only 5% of non-draftees That sounds excellent. But with our example: Actual Outcome Number Future draftees 200 Non-draftees 99,800 The model finds: 160 true future draftees (80% of 200) 4,990 false positives (5% of 99,800) So among the 5,150 players flagged as NFL prospects: 160 are real future draftees 4,990 are not Only about 3% of the flagged players actually make it. This surprises people because the model sounds strong, yet most positive predictions are still wrong. 3. Small differences matter enormously When outcomes are rare, tiny differences in probability become meaningful. For example: Player Draft Probability Average HS player 0.2% Strong prospect 2% Elite prospect 10% National blue-chip recruit 30% A 10% chance sounds low, but it's actually 50 times the baseline rate. People often interpret probabilities in absolute terms ("10% isn't much"), while forecasters care about them relative to the base rate. 4. Many important factors haven't happened yet A freshman's NFL prospects depend on events years in the future: Physical growth Injuries Coaching Position changes College choice Motivation Academic eligibility Competition level A model must predict not only current ability but also an entire developmental trajectory. This creates huge uncertainty. 5. Selection effects distort the data The players who reach college football are not random. For example: High school players are selected into college programs. College players are selected into starting roles. Starters are selected into combines and scouting evaluations. Prospects are selected into the draft. At each stage, the population changes. A variable that predicts NFL success among all high school players may not predict success among elite college players, and vice versa. 6. Rare events are especially sensitive to luck When outcomes are common, randomness averages out. When outcomes are rare, luck plays a larger role. Two equally talented players may have very different outcomes because: One tears an ACL. One gets recruited by a better college. One develops later physically. One enters the draft in a stronger or weaker year. For low base-rate events, chance often explains more of the outcome than people realize. 7. The "needle in a haystack" problem Most machine learning methods learn patterns from examples. If only 0.2% of observations are positive: There are relatively few successful cases to learn from. The model can easily overfit. Small quirks in the positive cases can look like meaningful patterns. This is why predicting rare diseases, financial fraud, terrorist attacks, startup unicorns, and NFL draft picks all share similar statistical challenges. A useful intuition Imagine trying to identify future NFL draftees among 100,000 high school players. The challenge is not finding someone who looks athletic. Thousands do. The challenge is distinguishing: the 200 who will eventually be drafted from the thousands who currently look almost as promising but won't make it. That's the core difficulty of low base-rate prediction: when the event is extremely rare, even strong signals leave substantial uncertainty, and most "promising" cases still won't experience the rare outcome
Posted: 06/20/2026 at 05:35 PM ET
(In response to this post by U2Hokie)

Thread Replies (56)

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Flanker 06/19/26 10:54 AM ET
I give you credit for using your VT statistics degree for us.
VaTechie 06/19/26 08:30 PM ET
I take issue with page 71, paragraph 5, sentence 3.**
Hate2SeeItEnd Hokie 06/19/26 06:54 PM ET
Wow I think you defended your thesis well. I will try to consolidate all
uber hokie 06/19/26 06:36 PM ET
Let's talk about these talented players in five years.
Flanker 06/20/26 06:31 AM ET
I gave this a like because it was…
VPI63 06/19/26 06:24 PM ET
You can click on the link at the bottom to see the previous year's analysis
Flanker 06/20/26 06:33 AM ET
hmmmmmm... so, yer sayin' thar's a, chance?
bourbonstreet 06/19/26 06:21 PM ET
I put the percentages below for the nine year period
Flanker 06/20/26 06:37 AM ET
Agree with you or not, I have to admire the amount of work you put in**
HokieNL 06/19/26 02:32 PM ET
Credibiltiy check: You said VT has better contributors than Ohio State. **
Techsupport 06/19/26 02:00 PM ET
FWIW, the entire notion that HS recruiting is a revenue stream...
Beerman 06/19/26 01:10 PM ET
You seem to be an expert in recruiting
Hardcore_Hokie 06/19/26 12:31 PM ET
Nobody can accurately predict with certainty the success of the recruits
Flanker 06/19/26 01:06 PM ET
I guess I don’t understand how this suggests Star ratings
Pride_and_Joy 06/19/26 11:26 AM ET
^^^This right here^^^ Hammer meets nail! @Flanker lots of great
U2Hokie 06/20/26 03:47 PM ET
Here’s a quick synopsis of the estimating small proportions
Pride_and_Joy 06/20/26 05:35 PM ET
P&J only looked at ONE year instead of all NINE years
Flanker 06/20/26 04:57 PM ET
@Flanker I'd like to see your contribution metric for 3 and 4 stars
U2Hokie 06/20/26 08:57 PM ET
Here you go
Flanker 06/21/26 10:09 AM ET
TY - Have a great Fathers day if appropriate!
U2Hokie 06/21/26 10:50 AM ET
My rebuttal
Flanker 06/21/26 11:17 AM ET
OK - keep on chuggin those numbers out as a historian/auditor 5 yrs later -
U2Hokie 06/21/26 04:37 PM ET
I'm doing one more year so I'll have TEN years of data.
Flanker 06/21/26 06:49 PM ET
10-4 TY - The Athletic reranked with the benefit of history and only 11
U2Hokie 06/21/26 07:05 PM ET
The fact is.......
2hhoop3 06/21/26 07:22 PM ET
Here is a great article too**
U2Hokie 06/20/26 03:48 PM ET
Interesting but I object to some of their methods and conclusions
Flanker 06/21/26 11:24 AM ET
Let me explain
Flanker 06/19/26 11:46 AM ET
If attrition rates include transfer portal I’m surprised it’s not higher
uber hokie 06/19/26 06:28 PM ET
This is a bit like deciding you don't want to use a couple
BuffaloTraceHokie 06/19/26 04:14 PM ET
Need a bunch of 4s for sure
crazylane 06/19/26 10:37 PM ET
Too many four stars are overrated
Flanker 06/20/26 08:48 AM ET
If you're not getting you're share of 4 stars(double digits maybe)
crazylane 06/20/26 04:40 PM ET
This analysis says dont worry - 3's are just as good if not better than 4's
U2Hokie 06/22/26 07:16 AM ET
Good analogy
Flanker 06/19/26 05:13 PM ET
I appreciate the response. And I won't go into it here, but...
BuffaloTraceHokie 06/24/26 09:49 AM ET
What do you mean by attrition rate? **
Pride_and_Joy 06/19/26 12:48 PM ET
All that means is that base rates of success are
Pride_and_Joy 06/19/26 04:24 PM ET
The rankings are certainly unreliable
Flanker 06/20/26 06:54 AM ET
I don’t know anyone who thinks the predictive validity
Pride_and_Joy 06/20/26 09:01 AM ET
It sounds like we might agree that the rankings are unreliable
Flanker 06/20/26 09:15 AM ET
You just plucked an arbitrary number out of thin air.
Pride_and_Joy 06/20/26 10:00 AM ET
So you're happy with 50% accuracy?
Flanker 06/20/26 10:43 AM ET
Also the NFL Draft is BS, the NBA Draft is BS, Stock Market is BS.
Hardcore_Hokie 06/20/26 04:21 PM ET
The percentage you set.....
2hhoop3 06/20/26 09:43 AM ET
I hope we agree that .300 is really bad for predictions.
Flanker 06/20/26 10:56 AM ET
Everyone should do.....
2hhoop3 06/20/26 11:16 AM ET
I conducted an AUDIT and the recruiting service algorithms FAILED.
Flanker 06/20/26 05:13 PM ET
You can see yourself ......
2hhoop3 06/20/26 06:00 PM ET
Sorry about that. I meant recruits that don't contribute.
Flanker 06/19/26 12:55 PM ET
I'll save you some time. You don't need to look at any other year.
UEMcGill 06/19/26 11:02 AM ET
I'm doing one more year. I'll just find other ways to waste time.
Flanker 06/19/26 01:08 PM ET
I sometimes wonder if the schools they select is another variable.
TekkNerd 06/19/26 11:19 AM ET
Picking the school with the best scheme and coaches is important.
Flanker 06/19/26 05:17 PM ET
I agree with this assessment. If a 4 star player is
vthogon 06/19/26 12:57 PM ET
High School Recruiting Rankings are meant to be a projection.
Flanker 06/19/26 05:23 PM ET