Per a 2013 PriceWaterhouseCoopers report entitled Experience Radar 2013: Lessons from the US Software Industry, 85% of respondents want their issues fixed within 24 hours. I’ve been working with a number of vendors lately who have very significant tails of open issues, reaching into weeks and months (and, for some, cases past their first-year anniversaries!) Surely customers who use very-complex software make an allowance for that 24-hour mark — but measuring the percentage of cases who do get resolved under this simple customer satisfaction milestone would be a good start, what do you say?
(Further down in the report 30% of respondents want to be notified proactively of bugs. Yet another task on our list.)