Formal arbitration proceedings to break the impasse in contract negotiations between the Baltimore Teachers Union and the Baltimore school board began today. In arbitration, each side sends a representative to present its case to a neutral, mutually agreed-upon third party. It's unclear how long the closed-door talks will last, but, presumably, once the arbitrator issues a recommendation, both sides will agree to abide by it.

The issue on the table, of course, is planning time. The school board and Andres Alonso want principals to be able to require teachers to spend one planning period a week collaborating. The union says teachers don't have enough planning time as it is.

See earlier entries on the dispute here, here and here.