In the Pay-Per-Share reward system, each miner is paid based on the number of shares they contributed to the pool. While the value of each share will fluctuate based on network difficulty and the current unit reward, the PPS reward system is said to take “luck” out of the equation because the payout for each share is not dependent on whether the pool was lucky or unlucky in a given time period. PPS is thus a static reward system. The “+” indicates that the pool also pays out the correct proportion of the Tx Fees to each miner when a block is found.