For most punters, explaining how odds are determined in sports betting is no challenge. The ones just starting in this trade might differ, though. So, if you want to discover what betting odds mean and the top factors influencing them, this article is for you. The first thing a professional bettor should do is to have a complete understanding of the popular odds formats. Mainly, we are talking about three types:
- Fractional Odds – Primarily used in Great Britain and Ireland, they will show you how much you’ll win if you bet a certain amount. For example, 3/1 odds (“three to one”) will indicate you’ll win three units for every unit you bet;
- Decimal Odds – Popular in mainland Europe, Canada, Australia, Africa, and some parts of Asia, decimal odds show you how much you’ll get in return if your stake is one unit. For instance, if you bet one unit on 3.00 odds, you’ll receive three units back: the stake (one unit) and the profit (two units). It is equal to the 2/1 fractional odds;
- American Odds – Popular mainly in the USA, they work around the 100 units of betting mark. So, if you bet on the favourite, the odds will come with a hyphen ahead, showing you how many units you have to bet to have a profit of 100 units. If your odds are Even (2.00) or greater, you’ll get them with a plus in front, and the amount will indicate your profit for 100 units invested.
To help quickly convert the odds to a more familiar format, websites like BetBrain.com created odds calculators to make it easy for beginners to shift between different formats. Now that we can get this out of the way let’s explore the factors that influence bookmaker odds more deeply.
Team’s Form
The recent form of the two players/teams involved in the sporting event plays a significant factor in setting the starting odds. A team that ranks second in a league but comes after four defeats in a row will always have a lesser chance of winning against a 7th-place opponent with four recent victories. 
Strength of Schedule
This factor is related to the Team’s Form and requires looking ahead. For instance, a team might have a national league fixture before a crucial Champions League game. Resting some essential players before the European match might be tempting, so the team’s odds for that game will rise, as they will have a lesser chance to win without the key players.
Considering Historical Trends and Patterns (H2H)
Here, we’re mainly talking about the Head-to-Head, or H2H. Also called a “timeline”, it consists of the recent games played by the two opponents against each other. However, we should consider other historical patterns when playing the odds. How do teams play away from home or their own stadium? How do they like an afternoon fixture compared to an evening one?
Factoring in Key Team and Player Statistics
Statistics are crucial in determining the main line for a bookmaker’s odds. Considering that markets Over/Under, BTTS, and Goalscorer revolve around key team and player statistics, it’s evident that both bookmakers and punters should analyse them carefully.
Recognising the Impact of External Factors
Besides the main actors, some external entities can influence a game’s outcome. As a consequence, bookmakers do what every respectable punter should, which is to analyse factors such as:
- Weather Forecast;
- Referees;
- Surface (Natural grass or artificial one).
Analysing Market Trends and Line Movement
The odds movements in time should be the best indicator of the public perception of a specific event. We’ll try to explain how even the best betting odds sites are heavily influenced by the amounts invested in a particular matchup.
Why Do Sports Betting Odds Change?
Odds shift depending on what people are betting on. If we have two sides (A and B), and they are equally likely to win, the starting odds for both will be 1 to 1 (Evens / 2.00 / +100). If more people bet on A to win, then the odds will shift so that B has a lesser chance of winning now. In simplistic terms, if ten people bet, and 6 of them bet on A, then A will have odds of 4 to 6 (bet six units to win 10), and B will have odds of 6 to 4 (bet four units to win 10). That would be completely break-even for the bookie, so they will “shade” the difference a bit through the rake (or the vig). What does this mean? That Even Odds will transform in 19/10 so the bookmaker can still profit.
What does “accept all odds movement” mean?
Because plenty of games receive an impressive volume of bets, odds can shift quickly. If you do your betting on a website, app or betting terminal, they can change without you noticing. If you are in the middle of selecting the odds for an accumulator, those you already picked on the slip might be modified until you finalize your bet. 
You can choose to “accept all odds movement” to have them automatically in the new state, or you can manually pick them up again.
