Well, the primary goal is, of course, to raise the income of minimum-wage earners. Failure criteria probably include things like a) a marked increase in businesses that rely on minimum-wage earners going out of business relative to other and/or b) a marked increase in unemployment among minimum-wage earners. I don't know what thresholds are reasonable. (Possibly confounding: as minimum wage increases, the available labor pool will also increase.)
In the case of Seattle, they commissioned two pieces of research for this ordinance:
UW Evans School of Public Affairs study: Local Minimum Wage Laws: Impacts on Workers, Families and Businesses [1]
University of California, Berkeley study: Who Would be Affected by an Increase in Seattle’s Minimum Wage? [2]
The second paper addresses a lot of the questions I suspect you're interested, and it addresses them with empirical evidence based on previous such experiments in other cities.
In the case of Seattle, they commissioned two pieces of research for this ordinance:
UW Evans School of Public Affairs study: Local Minimum Wage Laws: Impacts on Workers, Families and Businesses [1] University of California, Berkeley study: Who Would be Affected by an Increase in Seattle’s Minimum Wage? [2]
The second paper addresses a lot of the questions I suspect you're interested, and it addresses them with empirical evidence based on previous such experiments in other cities.
[1] http://murray.seattle.gov/wp-content/uploads/2014/03/Evans-r... [2] http://murray.seattle.gov/wp-content/uploads/2014/03/UC-Berk...