The performance metric is an indicator of how well a stake pool is performing. It is given as a percentage, and is measured by how many blocks the stake pool has produced compared to how many it was expected to produce. For example, if a pool only produces half the number of blocks that it was nominated for, its performance rating is 50%. This could happen because the pool has a poor network connection, or has been turned off by its operator.
Performance ratings make more sense over a longer period of time. If a pool has not yet been selected to produce a block in the current epoch, its performance rating will be 0%, even if it is likely to produce blocks later in the epoch. Performance ratings of over 100% are possible if a pool creates more blocks than it was nominated to produce.
Since this is a testnet, performance ratings should only be used as a guide, and may be affected by network uptime, updates, or parameter changes. In Daedalus and Yoroi, performance contributes to a stake pool’s ranking.