Pneumatic excitation is frequently used as a means of vibratory stress screening of electronic hardware. Although this type of excitation is unlike the more familiar electrodynamic excitation, the same criteria are used to evaluate both types of screens. This paper provides insight into the nature of the less well understood pneumatic exciter screening environment. A finite element analysis of a typical specimen and associated test fixtures was made. The assembled model was excited by both types of excitation and the resulting responses examined. The sensitivity of screening responses to specimen geometrical properties were considered. Analysis forms include the power spectral reduction of response data as is applied to actual test data. The limitations of comparing the two test types on this basis are discussed.