KCRW does a cost-benefit analysis of Proposition 15, a measure on the November 3 ballot that would raise property taxes for high-value commercial properties in California, bringing in more money for local governments and schools. And really understanding Prop 15 requires looking back at a much older measure. Prop 13 was passed in 1978, capping property taxes in California. That meant a big reduction in tax revenue, and public schools were heavily affected.