You are checking the Gokby statistics page, and you see a metric called "Pool Luck" sitting at 120% or 80%.
Is 120% good? Is 80% bad? Or is the pool stealing from you?
"Luck" in mining is a statistical term, not magic. Understanding it is crucial for judging a pool's performance.
The Dice Analogy
Imagine a mining pool is trying to roll a "6" on a dice to find a block.
- Statistically, you should roll a 6 once every 6 throws.
- 100% Luck: You roll exactly 6 times and get a 6. This is the perfect statistical average.
- High Luck (>100%): You roll the dice 12 times and still haven't found a 6. This is "bad luck" for the pool (it takes more work than expected).
- Low Luck (<100%): You roll the dice twice and find a 6 immediately. This is "good luck" (it took less work than expected).
Note: Some pools display it inverted (High % = Good). Check the pool's FAQ.
Does Luck Matter to You?
It depends on your payout model (see Article 6).
- If you use PPS (Pay Per Share): Luck does not matter to you. The pool pays you for your work regardless of whether they find blocks. The pool takes the risk of bad luck.
- If you use PPLNS: Luck does matter. Since you only get paid when a block is found, a period of "bad luck" means lower earnings for a few days. However, a period of "good luck" means bonus earnings.
The Law of Large Numbers
Over a short period (days), luck fluctuates wildly. A pool might have 50% luck one day and 200% the next.
However, over a long period (months), luck always averages out to 100%. Mathematics ensures this.
Conclusion
Don't panic if you see "Bad Luck" on the dashboard for a day or two. It is simply variance. As long as the pool's technology is sound (low latency, no rejected shares), the luck will mathematically balance out, and your profits will stabilize.
