How Most played and Trending are calculated

The front page of One Game a Day has two ranked sections, "Most played" and "Trending now". Both are calculated from measured play. This page explains what is measured and how the two lists are built.

What counts as a play

Opening a game page is not a play. Pressing Play is not a play either: that is counted separately, as a launch.

A session becomes a play when the game has been actively played for a minimum length of time. The minimum is a setting; its default is thirty seconds.

"Actively played" means all of these are true at once:

• The browser tab is visible.
• The browser window has focus.
• Keyboard focus is inside the game.

Time spent with the tab in the background, or with the game sitting unattended behind another window, does not accumulate.

The page reports active time to the site, and the site checks each report against the clock: it never accepts more play time than has really passed since the session began.

Unique players

For Trending, the site counts unique players per day: one visitor playing one game counts once that day, however many sessions they play.

Visitors are told apart without accounts, cookies or stored addresses. The privacy page explains the method.

A visitor who has switched measurement off, which the privacy page also lets you do, is not counted at all. Their plays do not appear in either ranking.

Most played

"Most played" ranks games by their number of plays.

• If any plays were counted in the last seven days, the ranking uses plays from those seven days, and the line under the heading reads "Ranked by plays in the last 7 days."
• If none were, the ranking uses all plays since release, and the line reads "Ranked by plays since release."

The "Most played" sort order on All games always uses plays since release.

Trending now

Trending looks for games that are gaining players, not games that are merely large.

It compares two windows of equal length:

• recent: unique daily players over the last W days, including today.
• prior: unique daily players over the W days before that.

The score is calculated like this:

velocity = (recent - prior) / (prior + k)
score    = velocity x ln(1 + recent)

The three numbers involved are settings. Their defaults are:

Setting	Default	Meaning
W, the window	3 days	Length of each of the two periods being compared.
Minimum players	5	Fewest recent unique players a game needs to be eligible.
k, the smoothing	5	Damps growth figures that are built on very small numbers.

The front page states the window in use, in the sentence under the "Trending now" heading.

Why the formula has two parts

Growth alone would favour tiny games. A game going from 2 players to 6 has tripled, while one going from 200 to 400 has only doubled.

Adding k to the bottom of the fraction damps that effect, and multiplying by the logarithm of the recent player count gives weight to games that people are really playing. With the default settings:

Game	prior	recent	velocity	score
Small	2	6	4 / 7 = 0.571	0.571 x ln(7) = 1.11
Large	200	400	200 / 205 = 0.976	0.976 x ln(401) = 5.85

The large game ranks higher, as it should.

The minimum-data rule

A game appears in Trending only when both of these hold:

• Its recent unique players reach the minimum.
• Its recent figure is higher than its prior figure. A game that is level or falling is not trending.

A game that does not qualify simply has no trending score. It is not given a small one, a random one or an estimated one.

The same honesty applies to whole sections. When no game qualifies, the section shows an explanation in place of a list:

• Trending says that nothing is trending yet and explains what it compares.
• Most played says that no plays have been counted yet.

Likewise, a game's play count is displayed only once it has at least one counted play, and a "Typical session" length only once it has ten.

New & noteworthy

This section is partly editorial and partly measured.

1. Editor's picks come first, in the order the team has set. They are marked "Editor's pick".
2. Then come releases from a recent period, thirty days by default, ordered by play-through rate: the share of launches that turned into counted plays. A game needs at least ten launches before its rate is used.
3. Remaining recent releases follow, newest first.

The game currently featured at the top of the front page is left out of this section.

How fresh the numbers are

Totals since release are updated as plays are counted. The seven-day figures and the trending scores are recalculated on a schedule, about every five minutes.

Pages are also cached briefly. A ranking can therefore lag real time by a few minutes.

Keeping the numbers honest

Several rules stop the rankings from being inflated:

• A play session can be opened only by the site, for a game that can really be played, and each session can be counted only once.
• Play time is checked against real elapsed time on the server.
• Trending counts unique players per day, so one visitor is worth one.
• Automated clients are ignored.
• There is a cap on how many sessions one visitor can add to one game in a day.

Both lists are computed from these figures alone. The site has no sponsored placements; see Partnerships.

Nothing is faked

No figure on the site is seeded, estimated or randomised. A new game starts at zero, and a section with too little data says so.

For how the rankings appear when you browse, see Finding games.