Odds are not fixed. Between the moment a market opens and kick-off, prices move as information and money arrive. A price that falls is said to be dropping or shortening; a price that rises is drifting. BetArchives records both ends of that move for every selection.
Dropping and drifting odds
- Dropping (shortening) odds: the price falls, for example from 2.40 to 2.00. The market now sees the outcome as more likely.
- Drifting odds: the price rises, for example from 2.40 to 2.80. The market now sees it as less likely.
In a three-way market a move on one outcome is always balanced by moves on the others: if the home win shortens, the draw or the away win (or both) drift.
Why odds move
- Team news and line-ups – the most common cause of large moves.
- Weight of money – heavy staking on one side pushes its price down.
- Information the public lacks – late moves sometimes reflect news that only becomes public later.
- Market correction – a price out of line with other bookmakers is pulled back.
How to measure a move
The simplest measure is the percentage change in price: (opening − closing) ÷ opening. A drop from 2.40 to 2.00 is a 16.7% drop.
More informative is the change in implied probability: 1 ÷ 2.40 = 41.7% becomes 1 ÷ 2.00 = 50%, an 8.3-point increase. Probability changes are comparable across favourites and outsiders; price changes are not. See how to read decimal odds.
Do dropping odds win more often?
In the archive so far, the price of the eventual result shortened between opening and kick-off in 39% of matches. The market therefore tends to move towards what happens, which is why closing prices are considered more accurate than opening ones.
But a move is not a guarantee. Many matches are won by the side whose price drifted, and a selection that has already shortened offers a lower return than it did at the opening price.
Spotting odds movement on BetArchives
Every match page shows the opening price beneath the closing price, with ▼ for a shortened price and ▲ for a drifted one. The odds analysis section points out when the market moved towards a result before kick-off, and the match lists show the opening price when you hover a price.
To study a league's moves, open its archive, for example the La Liga archive, and compare opening and closing prices match by match.
Figures in bold come from the last 298 finished matches in the archive and update automatically.
Frequently asked questions
What does it mean when odds drop?+
The bookmaker has lowered the price because the outcome is now seen as more likely, usually after team news or heavy staking.
What is the opposite of dropping odds?+
Drifting odds: a price that rises because the market now considers the outcome less likely.
Should I follow dropping odds?+
Odds movement is information about the market, not a betting system. Past movement does not guarantee future results; if you bet, only stake what you can afford to lose.