process
How many plays a system needs
A short hot streak is not a system. This chart shows how many plays you need before a win rate is worth trusting with real money.
What “significant” means here
A win rate only means something if enough plays sit behind it. Ten plays can look great and still be luck. Statistics show that in order to have a long-term win rate of 55%+ at a 95% confidence level, your win rate vs. sample size should sit at or above the line on the graph below. 55% is not the break-even. At −110 you need about 52.4% just to get your money back after juice. 55% is a higher bar: the system looks real, not a coin flip that paid the juice. Sports Insights published a clear writeup of this test.
How to read the chart
If a system sits below the line, the idea can still be good — keep the same rule and add plays. The labels are the marks I use.
What this means for your bankroll
Keep this in consideration when you go through historical Results. While the last 20 game stretch can be meaningful, it does not replace the lifetime record. 500 plays at 60% is a crucial mark for me on longer-term systems. A lot of my best NFL systems sit below that, because there are so many fewer games. That is why a lifetime system keeps the same unit through a losing week, and why a 2026 AI model stays at 1u: one season is still a short sample. I used this chart and this rationale when I set the unit on each system. I do not revisit that number because last week was red or green.
Example
Someone posts “this dog system is 8–2 this month.” Ten plays. A coin can do that. The same written rule at 180–120 over five seasons is a system. You do not raise the unit because of a good month, and you do not cut the lifetime unit because of a bad month.
What this does not tell you
The chart does not say next season will look the same. If enough people find the same edge, the market can close it. The same test does not apply to moneylines: those are not 50/50 bets, so the math is different. A strong lifetime record is not a reason to bet more than the posted unit on the next play. That unit was set when the rule was written.
Recap
- 55% is higher than break-even
- More plays, a lower win rate can still count
- NFL samples sit below 500 at 60%
- Lifetime vs last-20 on Results
- This chart is how I sized the units
- Do not change the unit after one week