# Weekly Fantasy Start-Sit Advice

Fantasy Math is a premium service for weekly start-sit advice.

HOW IT WORKS

: put in your matchup (you and your opponents lineup), the
players you're deciding between, get back the probability you win.

Other sites (Yahoo, ESPN, Fleaflicker) show win probabilities, but Fantasy
Math is the only site modeling player point projections as explicit
distributions. More on the advantages that gives below.

## Projections as Probability Distributions

"The fundamental problem in fantasy football isn't maximizing your expected
total points, it's maximizing the probability you score more points than
whoever you're playing this week."

Fantasy Math is able to tell you who maximizes your probability of winning
because it starts with full probability distributions for every player.

It looks something like this:

PPR RB, week 14 last year. CMC is good.

Remember, there's a subtle difference between setting your lineup to score the
most points possible, vs trying to score more than your opponent.

Working with full point distributions like Fantasy Math does (vs point
estimates or rankings) get at this difference by letting you take into
account:

#### Variance, or how boom-or-bust a player is

Variance

Say you're down by 45 points going into a Monday night CLE-HOU game with one
player to go. Would you rather start Will Fuller or Jarvis Landry? What if you
were down 10 points?

Normal rankings and projections can't factor this in at all. But since Fantasy
Math models the entire distribution, it can tell you that Will Fuller has
a higher change of scoring 45 or more than Jarvis Landry.

#### Correlation, the tendency of players' scores to move together.

Correlation

Once we have a projected distribution for each player, Fantasy Math takes
thousands of correlated draws from each one. This lets you factor real-life
correlations into your decision.

For example:

Imagine you have a close call — say

Tyler Lockett

vs

Stefon Diggs

— and your
opponent is starting

Russel Wilson

. The fact Wilson and Lockett's points
are positively correlated (about 0.44) might affect your optimal decision.

Precisely HOW it affects your decision depends on the rest of your matchup:

•

if you're heavily favored, the correlation might mean you should start Lockett as a hedge against Wilson blowing up

•

if you're the underdog, maybe you need Wilson to underperform AND Diggs do really well to have any chance at all, which means Diggs maximizes your probability of winning

Fantasy Math takes all this into account. And not only the correlation between
same team QB-WR, but every pair of simultaneous correlations (e.g. Lockett and
Wilson together are correlated, but they're also both correlated with Chris
Carson, DK Metcalf and the QB of the team Seattle is playing against)
— between same and opposing QB, RB, WR, TE, K, DST.

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model that'll be more accurate + flexible than ever. Enter your email to stay
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## The Second Best "Who Do I Start Advice" You Can Get

It's easier to understand why Fantasy Math is the best start-sit advice you
can get by considering the

second best

advice you can get:

I have an economics background, and I've always been a big believer in
efficient markets and the wisdom of crowds. I draft by

selecting the biggest
bargain according to
ADP

,
and my investments are in index funds.

Expert Consensus Rankings — where hundreds of experts submit their fantasy
rankings each week — are clearly the fantasy football equivalent of that. And
so if the goal is maximizing point totals, efficient markets would suggest
— just as index funds beat stock picking — that's the best most of us (even
experts) can expect to do.

At the risk of giving away some secret formula

, Fantasy Math is basically
ECR with correlations and player variance added on top (one cool thing: the
more experts disagree about a particular player, the wider his distribution).

Because the goal in fantasy is beat your opponent rather than maximizing your
total points, this gives Fantasy Math a slight edge over ECR, which is
probably way ahead of anything else itself.

## The Fantasy Math Edge

While real, the Fantasy Math edge is small.

The main reason for this is that optimal start-sit decisions are mainly driven
by the scale parameter (i.e. start the guy whose distribution is furthest to
the right), which traditional rankings and point estimates get at fine.
Correlations and shape (aka variance aka boom or bust) are secondary.

I'm not even sure — compared to just using

ECR

or

Boris Chen

(which is also based off of ECR) — the impact on
expected wins/share of league winnings is worth the price, just as a pure
monetary, expected value calculation. Probably depends on your entry fee.

But fantasy is a game of small edges, and good players won't rest until
they've uncovered every possible one.

If this sounds relatable — if you spend more time on fantasy than you'd care
to admit and won't be able to rest until you've wrung every last drop of win
probability out of your lineup each week — then Fantasy Math might be for you.

## What People Are Saying

"

I freaking love this

. It's a beautiful idea and so far looks like a great
execution of it."

—

Dylan Lerch, aka u/quickonthedrawl

"This is an

outstanding way to visualize the choices we make every week

and why there are not necessarily one size fits all "right" answers,

different curves make more sense for different lineups/matchups

."

—

Sigmund Bloom, Co-owner of footballguys.com

"

No other tool I've ever come across has done this

... I've considered
[incorporating correlations] as a competitive advantage of mine for a number
of years, but wasn't able to properly and consistently quantify those values
in a truly objective measure..."

—

Seth K

"It’s an

incredible site

. I have no idea how you worked the math into
this."

—

Ben R

"...this is the first site I have seen that looks like it might

match the
standards I'd have for a subscription service.

"

—

David S

### New models coming soon! Subscribe for updates

Fantasy Math is undergoing changes this offseason, including a rebuilt WDIS
model that'll be more accurate + flexible than ever. Enter your email to stay
tuned for updates.

Get Notified!