The SportsEdgePro blog

Data, systems, better decisions

Explainers, how-tos and data studies on betting the Betfair exchange with evidence — building rule-based systems, backtesting them without fooling yourself, and reading what the market has already priced in.

Data studyHorse racing
Favourite–longshot bias at Betfair BSP: does backing short prices still lose?

The oldest documented pattern in betting markets. Does the crowd still overbet longshots once the bookmaker margin is gone and you settle at BSP net of commission?
How-toHorse racing
Horse racing draw bias: where it matters and where it's folklore

Draw bias is a course, trip, going and field-size interaction — not one number. Where stall position decides a race, where it's a myth, and how to test it for your courses.
Data studyGreyhounds
Greyhound trap bias: what the BSP data says about draw advantage

"Trap 1 always wins" is not a strategy. How draw advantage really behaves across a large Betfair BSP sample — and how to check it for the tracks you bet.
How-toGreyhounds
How to build a greyhound betting system that isn't just curve-fitting

Hypothesis first, enough sample, out-of-time testing, and judging a rule set by its drawdown and shape rather than its headline ROI.
ExplainerFundamentals
What Betfair Starting Price (BSP) actually is — and why every backtest should use it

How the Betfair Starting Price is formed, how it differs from bookmaker SP and early prices, and why it is the only honest price to settle a backtest at.