Win rate
The percentage of runners in a group that won: wins divided by runners, multiplied by 100. It is not the share of all winners.
Starting-price ROI
Historical return on investment based on recorded starting prices. If one unit were hypothetically staked on every runner in a group, ROI compares gross winning returns with the total units staked. A positive historical ROI does not establish a future betting advantage.
Actual versus Expected (A2E)
A2E compares observed wins with expected wins derived from the market-implied probabilities used by the research system. An A2E above 1 means the group won more often than those probabilities suggested. The precise calculation depends on the available price data, eligibility rules and methodology.
Sample size and uncertainty
A small group can produce eye-catching figures because of one or two results. Examine the number of runners, races, meetings and years, as well as whether findings persist when the sample is split. The more filters applied, the more likely a striking result may be driven by chance.