For the third time in five years, teachers in the Oakland Unified School District are on strike with picket lines up, and the vast majority of the city's more than 30,000 students are missing school for a fourth day now. The teachers hit the bricks even though the district is offering what it considers a substantial raise, coming very close to meeting the union's financial demands.

Union members admit the two sides are not that far apart on economic issues, but the sticking point this time is not money. It's the wide gap between the two sides on so-called 'common good issues', which has left many parents frustrated and confused.

In this episode of Bay Current, KCBS Radio's Doug Sovern, Patti Reising and Bret Burkhart get some answers from Dr. Joseph McCartin, Executive Director of the Kalmanovitz Initiative for Labor and the Working Poor at Georgetown University.