Marc Martin was quoted in the Functionize article, "Estimating Testing Time: A Few Useful Guidelines," regarding quality/target error rates in terms of launching and testing new products.

So far we’ve discussed one metric: What’s it going to take to get the product out the door? But Marc suggests an even more important metric to consider: What’s the worst thing your product can do to the end-user?

Set a target error rate based on the criticality of the product. “A line of code driving a pacemaker is different from keeping your calendar, so a standard can and should vary,” says Marc.