Development or use of antimicrobial agents (AAs), e.g. antibiotics, often involves the conduct of experiments, in which the effectiveness of one or more AAs against bacterial populations is assessed, to determine effective treatments. In such experiments, the size of a bacterial population attacked by an AA is measured over time, to determine the bacterial killing effectiveness of the AA in question. Measurement may be done in a number of ways. According to one measurement option, optical methods can be used, by which a light beam is shone to a bacterial population suspended in a solution, and the size of the bacterial population over time is inferred by measuring the amount of the incident light that does not go through the suspension as a result of impedance by the bacterial cells at each moment. While this method is convenient and can produce virtually continuous measurements in real time, it faces the challenge that it cannot discriminate between dead or alive bacterial cells, since both impede the transmission of light through the suspension. The invention is a method aimed at addressing this problem. Specifically, the invention offers a way to analyze experimental data quantitatively and to draw useful conclusions, e.g. on the rate of bacterial killing induced by an AA at various dosing regimens. The method can be combined with related devices, whether currently available or to be developed, and can produce information useful in both efficient development and use of effective AAs.