A methodology was developed for predicting the human response from ATD (Anthropomorphic Test Device) tests or for improving the biofidelity of the ATD response. The ATD response and human response are considered as the output of a black box system, from which the relationship between the ATD tests and human tests was established using wavelet analysis. Based on the decompositions of both responses on a wavelet packet basis, a mapping matrix is built after executing a procedure that includes de-noising and compression, energy distribution analysis, correlation analysis and regression analysis, and spectral coherence analysis and transfer function analysis. With the mapping matrix, an ATD response is modified or reconstructed into the corresponding human response. The practical use of the methodology was illustrated in the analysis of a series of lateral impact tests conducted on a horizontal impulse accelerator with an ATD and human volunteers as the test subjects. The predictions from the ATD tests using this method have attained significant improvement in biofidelity.