This department is overstaffed and its efficiency is poor.
Tips
history
From 《礼记·坊记》: a gentleman would rather his salary fall short of his work than his work fall short of his salary. 人浮于食 ('people outweigh their rations') was later recast as 人浮于事 - people outweighing their jobs.
mistakes
The 浮 here means 'to exceed; to outstrip', not 'to float'. Think 'surplus' not 'buoyant'.