Tennis Quotient Support

Help, answers and how to reach us

What the app does

Tennis Quotient rates professional tennis players by the results of their matches. Each match earns points based on whether the player won or lost and on the opponent's rank on the ranking list in force when the tournament started. A player's value is the average points per match. You compare two players from the same tour with Cohen's d, an effect size that measures the difference between their averages in standard deviations.

Common questions

Why isn't the latest tournament in the app?

The match data is built into the app, and new versions of the app bring it up to date. The date the data runs through is shown at the top of the Matchup tab and on the Data & credits tab. To get newer data, update the app from the App Store.

Why is a match or an event missing?

Results come from BALLDONTLIE, and the source doesn't cover everything. Some Association of Tennis Professionals (ATP) tour events are missing each year, and ATP Challenger events aren't included. Women's Tennis Association (WTA) results start in 2024, and ATP results start in 2007. The Data & credits tab lists the known gaps.

What does "possible retirement" or "possible walkover" mean?

The data source doesn't mark retirements (when a player stops during a match) or walkovers (when a player withdraws before it starts). The app flags a match as a possible retirement when the score isn't a completed match, and as a possible walkover when there's no score. By default, possible retirements count and possible walkovers don't. You can change both on the Tuning tab.

How do I read Cohen's d?

A positive d means Player A has the higher average, and a negative d means Player B does. As a rough guide, about 0.2 is a small difference, 0.5 medium and 0.8 large. The confidence interval (CI) shows how precise the estimate is: a wide interval means the result is less certain, usually because there are few matches.

Why use the opponent's rank at the time and not today's rank?

Beating a player who was ranked 5th that week is a different result from beating the same player years later at a lower rank. The app always uses the ranking list dated on or before the start of the tournament.

I changed the points table. How do I go back?

On the Tuning tab, tap Use approved default. Your custom tables stay saved, and you can switch between them at any time. Every saved matchup records which table produced it.

How do I delete my saved matchups?

Your matchups, settings and custom tables are stored only on your iPhone. Deleting the app removes all of them.

Does the app need an internet connection or an account?

No to both. The app works offline and doesn't collect any personal information. See the privacy policy.

Data credit

Match results and rankings: BALLDONTLIE (balldontlie.io).