Abstract It is shown that there occur two easily distinguishable line shapes in DRM spectroscopy. These reflect the change of the integrated intensity of the signal transition when pump radiation is applied. They readily permit deductions concerning the position of the shared energy level. This result is useful for the analysis of complicated spectra, as is illustrated with examples.An expression is derived which permits the determination of the integrated intensity of absorption lines by DRM techniques alone. It does not require knowledge of the absolute value of the pump power and provides, therefore, a convenient basis for relative intensity measurements without recurrence to Stark effect modulation.