Terms of Use

Dota2ProTips is a personal prediction log. I — Greg Spencer — watch every single Tier 1 Dota 2 match. Before each series starts, I write down who I think is going to win and why. That's it.

There are no algorithms picking for me. No machine learning. No paid tipsters. Just one guy who has followed pro Dota for years, formed an opinion, and committed to it in writing before the draft even begins.

Every prediction is public, every result is tracked, and my accuracy is visible to anyone who visits. I can't quietly delete a bad call. That's the point.

Each prediction is written before hero selection. By the time the draft starts, the pick is already locked in. This matters because the draft in Dota 2 reveals a huge amount of information — predicting after it is significantly easier and far less honest.

My process for each match:

• Recent form — How has each team performed in the last 2–4 weeks? Momentum matters more than historical prestige.
• Head-to-head — How have these two teams matched up before, especially at this level of competition?
• Roster changes — Any recent stand-ins, bootcamps, or roster shifts that could affect performance?
• Tournament stage — Groups play differently than playoffs. Teams sometimes sandbag in groups to hide strategies.
• ELO rating — My custom rating system gives a structured view of where each team stands relative to each other.

After the match, I come back and write an aftermath — a short note on what actually happened, what I got right, and where I was wrong. Predictions without follow-up accountability are worthless.

ELO is a rating system originally developed for chess. The core idea: every team starts at a baseline rating, and after each match, points flow from the loser to the winner. Beat a stronger team → gain more points. Lose to a weaker team → lose more points.

My implementation is adapted for Dota 2 Tier 1 specifically:

The ELO ratings are updated manually after each tournament. They are not a live automated system — I review results and apply updates myself, which also lets me apply context (e.g. a roster standing-in doesn't reflect the team's true strength).

On every prediction card you'll see a small bar showing the expected win probability for each team. This comes directly from the ELO ratings using the standard formula:

A green bar means the predicted winner has more than 50% expected probability. Amber means they are the underdog. This gives you an instant read on how confident or upset-prone a prediction is.

A pick where the favourite wins is less impressive than a pick where the underdog wins. The probability bar keeps that context visible at all times.

Every finished match is marked as correct or incorrect. The tournament page shows a running accuracy percentage. The rankings page tracks ELO across all teams over time.

I aim to beat 60% accuracy across any given tournament. That sounds modest, but in a field where upsets are constant and the best teams in the world can lose on any given day, consistent accuracy above coin-flip is genuinely hard.

All data is stored openly. Nothing is hidden, edited, or removed after the fact.

Tier 1 is where the game is played at its highest level. ESL One, PGL, The International — these are the tournaments that matter. The teams are the best in the world, the preparation is serious, and the results are meaningful.

Covering lower tiers would mean tracking hundreds of teams, many of which are inconsistent by nature. Predictions there would be noise. Tier 1 is focused, watchable, and worth analysing carefully.