EVERY TIME it seems the District’s child welfare agency is making progress, there’s a crisis or a change of leadership. Reform is fragile in one of the city’s most critical departments. That’s why it is important for D.C. Mayor Vincent C. Gray (D) to act quickly to stabilize the agency in the wake of the planned departure of its fifth director in 10 years.

Roque R. Gerald, serving as interim director under Mr. Gray, has announced he will be leaving as director of the city’s Child and Family Services Agency at the end of this month. Former mayor Adrian M. Fenty put him in charge of the agency in July 2008, when it was being rocked by the Banita Jacks tragedy. The discovery of the bodies of four girls whose family troubles had been brought to the attention of — but mishandled by — the agency resulted in a deluge of hot-line calls and a massive backlog of cases. The department was in crisis.

Mr. Gerald leaves a department stronger than the one he inherited. The court monitor in a long-running federal lawsuit credits him with stabilizing the agency and improving management accountability and performance; U.S. District Judge Thomas F. Hogan even approved a plan that could lead to the city being removed from court oversight.

Nonetheless, it is clear from the report by monitor Judith W. Meltzer of the Center for the Study of Social Policy that significant problems persist after two decades. Case management is uneven, there’s a gap between what the agency promises to do and what it can do, and there is a threat of harmful budget cuts. Uncertainty in leadership only adds to the problems.

Other cities with larger populations and more complex child welfare issues have managed to get their houses in order. It’s time that the District follow suit.