Effort and luck: reading a pool round

A round is everything that happens between two blocks found by the pool. Two numbers describe it. Effort is how much work the round consumed, in block-equivalents: the sum of every share's difficulty divided by the *network* difficulty at the moment it was submitted. A round at 150% effort did one-and-a-half blocks' worth of guessing before landing one.

Luck is the same information from the payout's point of view: expected shares ÷ actual shares × 100%. Expected 1,000,000 shares and the block came after 500,000? Luck = 200% — very lucky, half-price block. Needed 2,000,000? Luck = 50% — a slow round, not a broken pool.

Every block attempt is independent — the lottery has no memory. Past bad luck does not make future good luck more likely, so pool-hopping during an unlucky streak pays switching costs for zero expected gain. A pool at 70% luck for a week is not "due"; a pool at 130% luck is not "hot". Luck below 100% for a day is noise; luck below 100% for a month is *still* noise — independence cuts both ways.

What sustained bad luck *can* legitimately tell you: nothing about the future, but something about the pool's operation — look for rising stale rates or hashrate dropout around the slow rounds (infrastructure problems) rather than mystical mean-reversion.

• Per-block effort on recent blocks — scatter around 100% is the healthy signature.
• Rolling luck (24h / 7d) — wide but bounded swings; treat anything inside ~50–200% as ordinary.
• Blocks per hour vs the pool's hashrate share — the two should agree on average; persistent disagreement means stale shares or reporting lag.

Analytics sections chart pool luck over time from the pools' public APIs — enough to watch the scatter and internalize what ordinary randomness looks like before trusting anyone's "unlucky pool" claim.