What Is “Pool Variance” and How Does It Affect Mining Profitability?
Pool variance is the fluctuation in the time it takes a mining pool to find a block compared to the statistically expected time. High variance (or "bad luck") means it takes longer, leading to unpredictable and sometimes delayed payouts.
Low variance (or "good luck") means blocks are found faster. Variance introduces risk, which the PPS model absorbs and the PPLNS model passes on to miners.