In a lithographic apparatus, a slip of a patterning device relative to a support, the support being constructed to support the patterning device, may be provided by: measuring a position of the support relative to a structure of the lithographic apparatus; measuring a position of the patterning device relative to the structure of the lithographic apparatus; determining a correlation between the position of the patterning device and the position of the support; and deriving from the correlation a slip of the patterning device relative to the support. The structure may include a projection system to project a radiation beam patterned by the patterning device onto a target portion of the substrate. The projection system may be connected to a frame, such as a metrology frame of the lithographic apparatus.