Call center error rate: Is there an industry standard?

There is no standard error rate that can be applied generally across the board. Each business is unique in its approach and tolerance to error. What may be a perfectly acceptable error ratio in your business or industry could be viewed as extremely high in another. Your tools and processes can also influence error rate. I would recommend doing some benchmarking with similar call centers and organizations to determine where you are in relation to your peers, and then set metrics according to your overall business strategy.