What do you call a $10 million-a-year public school fund for which “no historical records” are available to document how and where the money was spent? Fairfax County Public Schools calls it the “staffing reserve.” Irate parents refer to it as a slush fund.

The theory behind the staffing reserve is simple. It allows FCPS to hire additional teachers if there’s an unexpected surge in enrollment. But it doesn’t work that way in practice. For example, when the principal of Wolftrap Elementary asked for additional help because a third-grade class had 36 students, the school was allotted .2 teachers from the staffing reserve — enough for one teacher to come in just one day a week.