Measuring results: ROI, yield and variance

If you don't measure honestly, you can't tell skill from luck — and in a low-scoring sport, luck wears a very convincing disguise. A few simple metrics keep you grounded.

ROI and yield

ROI (return on investment) is your net profit divided by the total amount you staked, as a percentage. Yield is the same idea expressed over total turnover. If you staked 100 units across a season of 1X2 and over/under bets and ended +8 units, your yield is 8%.

A sustained yield of even a few percent is genuinely good — professional football bettors often live in low single digits after the bookmaker's overround. If your tracker shows 30%, you almost certainly haven't run long enough yet.

Why win rate alone lies

Counting how often you win is misleading without the odds. Backing short-priced home favourites and winning 70% of the time can still lose money; hitting 40% on value-priced draws can be hugely profitable. A bet is only "good" relative to its price — never judge results by hit rate alone, especially when the draw makes the favourite look safer than it is.

Variance and the short run

Variance is the natural swing of outcomes around your true edge, and football's scarcity of goals makes it especially savage. Even a profitable approach will have losing weeks — sometimes losing months. The short term tells you almost nothing:

• A 10-bet sample is noise.
• Hundreds of bets begin to reveal a real signal.

Track every bet — stake, odds, market, result. Judge the process over a large sample, not the last few accumulators.