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
Thread Replies (56)
I give you credit for using your VT statistics degree for us.
-- VaTechie
Jun 19, 2026 at 08:30 PM ET
VaTechie
•
06/19/26 08:30 PM ET
I take issue with page 71, paragraph 5, sentence 3.**
-- Hate2SeeItEnd Hokie
Jun 19, 2026 at 06:54 PM ET
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
Jun 19, 2026 at 06:36 PM ET
uber hokie
•
06/19/26 06:36 PM ET
Let's talk about these talented players in five years.
-- Flanker
Jun 20, 2026 at 06:31 AM ET
Flanker
•
06/20/26 06:31 AM ET
I gave this a like because it was…
-- VPI63
Jun 19, 2026 at 06:24 PM ET
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
Jun 20, 2026 at 06:33 AM ET
Flanker
•
06/20/26 06:33 AM ET
hmmmmmm... so, yer sayin' thar's a, chance?
-- bourbonstreet
Jun 19, 2026 at 06:21 PM ET
bourbonstreet
•
06/19/26 06:21 PM ET
I put the percentages below for the nine year period
-- Flanker
Jun 20, 2026 at 06:37 AM ET
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
Jun 19, 2026 at 02:32 PM ET
HokieNL
•
06/19/26 02:32 PM ET
Credibiltiy check: You said VT has better contributors than Ohio State. **
-- Techsupport
Jun 19, 2026 at 02:00 PM ET
Techsupport
•
06/19/26 02:00 PM ET
FWIW, the entire notion that HS recruiting is a revenue stream...
-- Beerman
Jun 19, 2026 at 01:10 PM ET
Beerman
•
06/19/26 01:10 PM ET
You seem to be an expert in recruiting
-- Hardcore_Hokie
Jun 19, 2026 at 12:31 PM ET
Hardcore_Hokie
•
06/19/26 12:31 PM ET
Nobody can accurately predict with certainty the success of the recruits
-- Flanker
Jun 19, 2026 at 01:06 PM ET
Flanker
•
06/19/26 01:06 PM ET
I guess I don’t understand how this suggests Star ratings
-- Pride_and_Joy
Jun 19, 2026 at 11:26 AM ET
Pride_and_Joy
•
06/19/26 11:26 AM ET
^^^This right here^^^ Hammer meets nail! @Flanker lots of great
-- U2Hokie
Jun 20, 2026 at 03:47 PM ET
U2Hokie
•
06/20/26 03:47 PM ET
Here’s a quick synopsis of the estimating small proportions
◄
-- Pride_and_Joy
Jun 20, 2026 at 05:35 PM ET
Pride_and_Joy
•
06/20/26 05:35 PM ET
P&J only looked at ONE year instead of all NINE years
-- Flanker
Jun 20, 2026 at 04:57 PM ET
Flanker
•
06/20/26 04:57 PM ET
@Flanker I'd like to see your contribution metric for 3 and 4 stars
-- U2Hokie
Jun 20, 2026 at 08:57 PM ET
U2Hokie
•
06/20/26 08:57 PM ET
TY - Have a great Fathers day if appropriate!
-- U2Hokie
Jun 21, 2026 at 10:50 AM ET
U2Hokie
•
06/21/26 10:50 AM ET
OK - keep on chuggin those numbers out as a historian/auditor 5 yrs later -
-- U2Hokie
Jun 21, 2026 at 04:37 PM ET
U2Hokie
•
06/21/26 04:37 PM ET
I'm doing one more year so I'll have TEN years of data.
-- Flanker
Jun 21, 2026 at 06:49 PM ET
Flanker
•
06/21/26 06:49 PM ET
10-4 TY - The Athletic reranked with the benefit of history and only 11
-- U2Hokie
Jun 21, 2026 at 07:05 PM ET
U2Hokie
•
06/21/26 07:05 PM ET
Interesting but I object to some of their methods and conclusions
-- Flanker
Jun 21, 2026 at 11:24 AM ET
Flanker
•
06/21/26 11:24 AM ET
If attrition rates include transfer portal I’m surprised it’s not higher
-- uber hokie
Jun 19, 2026 at 06:28 PM ET
uber hokie
•
06/19/26 06:28 PM ET
This is a bit like deciding you don't want to use a couple
-- BuffaloTraceHokie
Jun 19, 2026 at 04:14 PM ET
BuffaloTraceHokie
•
06/19/26 04:14 PM ET
Need a bunch of 4s for sure
-- crazylane
Jun 19, 2026 at 10:37 PM ET
crazylane
•
06/19/26 10:37 PM ET
Too many four stars are overrated
-- Flanker
Jun 20, 2026 at 08:48 AM ET
Flanker
•
06/20/26 08:48 AM ET
If you're not getting you're share of 4 stars(double digits maybe)
-- crazylane
Jun 20, 2026 at 04:40 PM ET
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
Jun 22, 2026 at 07:16 AM ET
U2Hokie
•
06/22/26 07:16 AM ET
I appreciate the response. And I won't go into it here, but...
-- BuffaloTraceHokie
Jun 24, 2026 at 09:49 AM ET
BuffaloTraceHokie
•
06/24/26 09:49 AM ET
What do you mean by attrition rate? **
-- Pride_and_Joy
Jun 19, 2026 at 12:48 PM ET
Pride_and_Joy
•
06/19/26 12:48 PM ET
All that means is that base rates of success are
-- Pride_and_Joy
Jun 19, 2026 at 04:24 PM ET
Pride_and_Joy
•
06/19/26 04:24 PM ET
The rankings are certainly unreliable
-- Flanker
Jun 20, 2026 at 06:54 AM ET
Flanker
•
06/20/26 06:54 AM ET
I don’t know anyone who thinks the predictive validity
-- Pride_and_Joy
Jun 20, 2026 at 09:01 AM ET
Pride_and_Joy
•
06/20/26 09:01 AM ET
It sounds like we might agree that the rankings are unreliable
-- Flanker
Jun 20, 2026 at 09:15 AM ET
Flanker
•
06/20/26 09:15 AM ET
You just plucked an arbitrary number out of thin air.
-- Pride_and_Joy
Jun 20, 2026 at 10:00 AM ET
Pride_and_Joy
•
06/20/26 10:00 AM ET
So you're happy with 50% accuracy?
-- Flanker
Jun 20, 2026 at 10:43 AM ET
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
Jun 20, 2026 at 04:21 PM ET
Hardcore_Hokie
•
06/20/26 04:21 PM ET
I hope we agree that .300 is really bad for predictions.
-- Flanker
Jun 20, 2026 at 10:56 AM ET
Flanker
•
06/20/26 10:56 AM ET
I conducted an AUDIT and the recruiting service algorithms FAILED.
-- Flanker
Jun 20, 2026 at 05:13 PM ET
Flanker
•
06/20/26 05:13 PM ET
Sorry about that. I meant recruits that don't contribute.
-- Flanker
Jun 19, 2026 at 12:55 PM ET
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
Jun 19, 2026 at 11:02 AM ET
UEMcGill
•
06/19/26 11:02 AM ET
I'm doing one more year. I'll just find other ways to waste time.
-- Flanker
Jun 19, 2026 at 01:08 PM ET
Flanker
•
06/19/26 01:08 PM ET
I sometimes wonder if the schools they select is another variable.
-- TekkNerd
Jun 19, 2026 at 11:19 AM ET
TekkNerd
•
06/19/26 11:19 AM ET
Picking the school with the best scheme and coaches is important.
-- Flanker
Jun 19, 2026 at 05:17 PM ET
Flanker
•
06/19/26 05:17 PM ET
I agree with this assessment. If a 4 star player is
-- vthogon
Jun 19, 2026 at 12:57 PM ET
vthogon
•
06/19/26 12:57 PM ET
High School Recruiting Rankings are meant to be a projection.
-- Flanker
Jun 19, 2026 at 05:23 PM ET
Flanker
•
06/19/26 05:23 PM ET