Normalisation is the process of modifying a set of post‐mortem human subject (PMHS) response data to better represent that of a standard sized human. This improved method is based on the fact that all plots of deflection energy versus deflection for the thorax are of constant slope. The deflection energy is the integral of the applied impact force over the deflection measured by a chestband up to the point of maximum deflection. Standard sized human thorax deflection energies and slopes are found from multivariate analyses relating energy and slope, separately, to the anthropometric data for all subjects. Force is the spatial derivative of the linear deflection energy curve and is a constant. The resulting rectangular force versus deflection curve leads to scale factors for force, deflection, elastic stiffness, the viscous constant, and time, assuming a two element solid viscoelastic model. Subject effective mass and post‐impact velocity were calculated from conservation of energy and impulse equals momentum, solved simultaneously, providing scale factors for effective mass and subject velocity at maximum deflection. The time histories and force versus deflection have been plotted, the standard deviation targets over‐plotted, and coefficients of variation calculated. Results have been qualitatively and quantitatively compared to previous methods.