Using Betting Odds to Predict Sports Outcomes: Market Efficiency Research

Betting odds are not just prices — they are probabilistic forecasts shaped by millions of pounds in market activity. Decades of academic research have examined how well these prices predict actual outcomes.

What the Research Shows

The landmark study by Forrest, Goddard, and Simmons (2005) analysed over 30,000 football matches and found that bookmaker odds were statistically well-calibrated. Events priced at 50% probability occurred close to 50% of the time. Later work by Štrumbelj (2014) confirmed that closing odds outperformed even sophisticated Elo-based models.

Similar findings apply across sports. Woodland and Woodland (1994) demonstrated efficiency in baseball run lines, while Spann and Skiera (2009) found European football markets to be among the most efficient prediction mechanisms available.

The Favourite-Longshot Bias

The most persistent inefficiency documented in research is the favourite-longshot bias. Across dozens of studies spanning horse racing, football, and tennis, longshots are consistently overpriced. A bet priced at implied probability 5% wins less than 5% of the time on average.

For a £10 bet at odds of 20.00 (implied probability 5%), you would need to win more than once every 20 attempts to break even. Research suggests such outcomes occur closer to once every 23-25 attempts, eroding value for longshot backers.

When Markets Fail

Markets are least efficient where information is scarce and liquidity is low. Lower-league football, early-season fixtures, and niche sports offer the most realistic opportunities for informed bettors.

In-play markets can also lag behind events on the pitch, particularly for goals that take seconds to process through automated feeds. However, bookmakers have significantly closed this gap with faster data and trading algorithms.

Practical Implications

Treat closing odds as a baseline truth. If your model consistently agrees with the market, you likely have no edge. Value exists only where your probability assessment systematically differs from the closing line — and where that difference survives the bookmaker margin.

Track your results against closing line value (CLV). Academic consensus holds that consistently beating the closing line is the strongest indicator of long-term profitability in sports betting.

Frequently Asked Questions

Are betting odds accurate predictors of sports results?+

Yes. Academic research consistently shows that closing odds — the final odds before an event starts — are among the most accurate probabilistic forecasts available. A study by Štrumbelj (2014) found closing odds outperformed complex statistical models in football prediction accuracy.

What is market efficiency in sports betting?+

Market efficiency means that odds fully reflect all available information. In an efficient market, no bettor can consistently achieve positive returns because prices already incorporate every relevant factor. Studies show major sports markets are semi-strong efficient — they quickly absorb public information.

What is the favourite-longshot bias?+

The favourite-longshot bias is a well-documented phenomenon where bettors overvalue longshot outcomes and undervalue favourites. This means odds on heavy underdogs tend to offer worse value than they appear, while short-priced favourites are slightly underpriced relative to their true probability.

Can you still profit if betting markets are efficient?+

Strictly efficient markets would make consistent profit impossible. However, most research classifies betting markets as near-efficient rather than perfectly efficient. Small edges can exist in niche markets, in-play situations, or where bookmaker models lag behind breaking information such as late team news.

Do closing odds outperform opening odds?+

Yes. Research consistently shows closing odds are more accurate than opening odds because they have absorbed more information and betting volume. The difference between opening and closing lines is itself informative — significant line movements often indicate where sharp money has landed.