About ET Parlays

8:51 in the morning, Thursday, July 31, 2025. I’m making a two-page PDF about four hitters in a Rays-Yankees game.

Splits against righties. A five-game hitting streak. A note that the wind is blowing in at Yankee Stadium at 12 miles an hour. The hashtag #ETParlays, which at that point was the name of a PDF. And at the very bottom, where I forgot to delete it, a takeout order: fried rice or ice cream or cream cheese rangoons.

By September it was nine pages. A hits watchlist, total bases, home runs. A column called “Why We Like Him.” Ohtani, 1+ hit, 89%. Judge, 82%. Then the parlays I built out of them: a 3-leg, a 4-leg, a 7-leg I labelled “Aggressive,” and a 7-leg lotto.

I sent them to a couple of friends and most of the people I worked with at the hospital who watched sports and bet on them. Builder Thursdays. I knew there was variance. That’s why they were lists. People could make their own decisions, or their own parlay.

By April the PDF was an app, the lists were graded, and my own landing page said 61%.

April 22, 2026. Late afternoon, home, running audits on the landing page. I checked the number against the database.

764 graded. 36.9%.

The first thing I thought wasn’t “hide it.” It was: how do we improve that, or is the sample just small?

I didn’t lower the number. I deleted the whole bar and shipped nothing in its place. The site went four months without a performance stat on it, because the only honest number I had was one I hadn’t earned yet.

A week earlier I’d deleted the button that built the parlay for you. The thing I used to do by hand on Thursdays.

I’d built a machine to check the book’s numbers. The first number it caught was mine.

What I found when I checked

Since then, the MLB batter reads that make the board get graded after the game, win or lose. Here is the record. It’s read from the database when this page loads, so it can’t drift the way the 61% did.

11,558 reads graded between April 14, 2026 and September 18, 2026. MLB batter props that made the board. One season, not ten.

The grade letters are set per prop type, so pooling them here would mix bases. The probabilities are comparable, so those are what’s below: what the model said, against how often it happened.

Bands with fewer than 30 graded reads aren’t shown, because a number built on twelve outcomes isn’t a number. Strikeout props are left out until their number is on the same basis as the rest.

The gap is widest at the top. When the model said 80 to 90%, those reads hit 63%. The further up the board you look, the more the confidence outran the result.

Parlays were worse. As of September 2, 2026, the legs inside them said 71% and hit 50%. Across 348 parlays we expected about 101 winners and got 25. The combined odds we displayed were not achievable.

On August 24 I started cutting the MLB parlay leg numbers down by how much each prop type had actually missed, measured on 306 graded slips, before multiplying them. Home run legs get cut the most. Then a same-game correlation adjustment goes on top, and the face says so. Whether that fix worked is not graded yet. Most of those 348 slips predate it.

Everywhere else in the Lab, including Slip Check, the combined number still multiplies the legs straight across. Treat it as optimistic. The next number that goes on this page is whether the August fix held, either way.

The full version of all of this, every denominator, how a read is graded, how much of the board never gets graded, and each place the numbers still run hot, is on the methodology page.

I’m putting this on the About page because it’s the only proof of method you can check yourself. The full record is in the Lab. It includes the misses.

Things I tried that didn’t work

Each one had a test set in advance and failed it.

• A hot-streak boost. May 3. Replayed the 2024 season, 38,054 batter-games. Hitters on a hot two weeks hit about 7 points below what the model already said. Widening the streak effect made every band worse. Reverted.
• An NBA totals model. May 9. Replayed 1,236 games. It under-projected high-scoring games by 8 to 21 points. The totals number is still held back from the cards.
• A rule to suppress KBO reads the model liked but the market didn’t. August 20. This one hurt. A friend used those reads every day, and I kept chasing an answer to the variance. When he texted me the KBO leans were off, I had to see the numbers myself before I could respond. They were eye-opening. The KBO reads came down that day. Then the replay killed my fix too: it would have deleted the only segment that made money at its price and kept the one that lost. Nothing shipped, and I had to tell him so.
• Searching my own data for a hidden edge. September 2. 201 slices. The best result was inside the range pure chance produces. Nothing found. That one is on the list on purpose.

What the Lab does

You bet wherever you already bet. ET is the Lab you open first.

• Every read comes with the reasoning shown, and every stat explained next to the number, in plain words. This is the thing members mention most.
• Paste any slip and it checks every leg before you place it, and names the one dragging the slip down.
• Every read that makes the board is graded after the game, and the record is on this page and in the Lab, misses included, so you can check ET instead of following ET.

A grade is a read, not a promise. Sometimes the best bet is no bet at all.

What it refuses to do

ET isn’t a sportsbook. It takes no wagers, holds no money, and takes no cut of anything you bet.

Options, not parlays. Nothing here is picked, staked, or placed for you. A button that bets for you is a button that thinks for you, and that’s how you stay the fish.

The subscription is flat. ET makes the same money whether you bet once this month or a hundred times. Almost nothing else in this industry can say that.

Straight up: no sportsbook pays ET anything today. If that ever changes, it gets written here first, and it won’t change the numbers we show you. What no book can buy is a grade, a ranking, or a spot on the board.

Who it’s for

If you go back and look at the slip after it loses, this is for you. If you’ve ever asked “was that a bad beat, or a bad bet?” and not liked that you couldn’t answer, this is for you.

If you want to be told what to bet, it isn’t. Plenty of people will do that. None of them will show you their misses.

Who’s writing this

I’m Eddie. I’m a nurse on a surgical progressive care unit. The monitor room calls: your patient’s in the 140s. I’m rushing down the hall, and when I get there they’re just chillin in bed. Happens all the time. The number is where you start, not where you stop. You look at the person. And when I’m wrong, I’d rather find out early than quietly.

ET started in the summer of 2025 as spreadsheets, Statcast pasted into charts, and a PDF I sent to coworkers on Thursdays. I taught myself to build the rest. I work Friday to Sunday, which is when the games are, so most of it gets built on weeknights. A friend started texting me their slips in April so I’d check the legs by hand. That’s where Slip Check came from. The first version was me.

I’m not going to pretend I know what’s going to happen tonight. I can show you what the number says, what it’s said before, and how often that turned out to be true.