Forecaster
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tetlock-style-economists - Predictions for:

Jannik Sinner wins US Open

Made on 8/11/2026
Source Document
45%

Clarify the Event

Event: Jannik Sinner wins the US Open 2026. Resolution Date: September 30, 2026.

Estimate the Historical Base Rate

Winning a Grand Slam is difficult, with typically only a few players having a realistic chance each year. Historically, as a top-ranked player, Sinner may have a base winning probability around 10% to 15% for a given Grand Slam.

Break the Problem into Independent Factors

  1. Health
  2. Current Form and Momentum
  3. Competition Strength
  4. Historical Performance at US Open and on Hard Courts
  5. External Factors (e.g., weather, draw luck)

Estimate Each Factor Separately

  1. Health: Sinner has a knee inflammation issue. This poses a risk, but with rest, he may still perform well. Approximate impact: reduces his chance to 7%.

  2. Current Form and Momentum: His limited play since Wimbledon poses a concern, but he has previously succeeded without extensive lead-up matches. This uncertainty may drop his likelihood slightly to 6%.

  3. Competition Strength: If Alcaraz is absent or underprepared, his chances improve. However, Zverev and Djokovic still pose significant threats. Modifies probability back to 7%.

  4. Historical Performance at US Open and on Hard Courts: As a strong performer on hard courts and given his No. 1 ranking, this factor enhances his chances to about 10%.

  5. External Factors: External conditions such as weather are neutral or slightly positive due to his adaptability.

Recombine into an Overall Probability

By weighing the factors and noting his status and competition, the predicted probability of Sinner winning the US Open is approximately 45%.

Check for Overconfidence

The combined impact of health and competition suggests a slightly lower probability. Top players’ matches are often decided by narrow margins, and recent form is less certain.

Imagine Why You Could Be Wrong

  • Health Setback: The knee issue might not improve as expected, impacting performance.
  • Underestimation of Rivals: If Alcaraz returns fully fit or another player unexpectedly finds form, it could lower Sinner's chances.
  • Match Fitness: Limited match play might pose greater challenges than anticipated, particularly in a five-set format.
Made on 8/6/2026
Source Document
40%

1. Clarification of the Event

Forecasting the likelihood of Jannik Sinner winning the US Open by September 30, 2026.

2. Estimate the Historical Base Rate

  • Historically, the No. 1 ranked player entering the US Open has a relatively high chance of winning, though it varies significantly year-on-year. Average winning probability for top contenders (e.g., top 3 ATP players) is usually around 15-25%.
  • Sinner's previous win in 2024 and final appearance in 2025 offer a solid base at the US Open.

3. Break the Problem into Independent Factors

  • Current Form and Injury Status
  • Historical US Open Performance
  • Head-to-Head versus Major Rivals
  • Mental/Physical Health Signals

4. Estimate Each Factor Separately

  • Current Form and Injury Status: Despite minor alarm over recent medical checks, Sinner is cleared and ready for competition, performing exceptionally on hard courts, winning multiple Masters 1000 titles. Given no explicit injuries, continue with a 30% chance boost from form.

  • Historical US Open Performance: Previous champion and finalist. Strong history gives a 10% boost.

  • Head-to-Head vs. Rivals: The rivalry with Alcaraz poses a threat, especially with a 1-6 record against him since 2024, which slightly dampens his prospects by 15%.

  • Mental/Physical Health Signals: Recent medical checks and early Roland Garros exit introduce a potential risk reducing probability by 5%.

5. Recombine into an Overall Probability

  • Base Rate: 15% (Top 3 player average)
  • Current Form Boost: +30%
  • US Open Record Boost: +10%
  • Rivalry Diminisher: -15%
  • Health Concern Diminisher: -5%

Total Adjusted Probability: 40%

6. Check for Overconfidence

A probability range greater than 50% would be overly optimistic given the competitive field and potential uncertainties.

7. Imagine Why You Could Be Wrong

  • If Sinner has undisclosed health issues or faces an enhanced Alcaraz matchup, this could lower his actual chances.
  • Changes in hard-court play dynamics or other emerging players might shift expected outcomes.
  • Psychological factors post-injury could either enhance focus or detract from performance.