How Does the PPS Payout Scheme Transfer Risk from Miners to the Pool Operator?

In the Pay-Per-Share (PPS) scheme, the pool operator pays miners immediately for every share of work they submit, regardless of whether the pool actually finds a block. The payment is calculated based on the expected value of a block reward.

This guarantees a stable, predictable income for the miner. The pool operator assumes the risk of variance, meaning they pay out even if the pool experiences a "bad luck" streak and fails to find blocks commensurate with the expected payout.