Provided herein is a method for determining the temporal progression of a biological phenomenon which may affect a studied subject, the method including the steps of providing first data relative to biomarkers for the studied subject, the biomarkers being relative to the progression of the biological phenomenon, providing a numerical model, converting the first data into at least one point on the same Riemann manifold, and using a numerical model to determine a temporal progression for the biological phenomenon for the studied subject, the numerical model being a function in a Riemann manifold, the numerical model associating to values of biomarkers a temporal progression trajectory for the biological phenomenon and data relative to the dispersion of the progression trajectory for the biological phenomenon among a plurality of subjects, the numerical model being obtained by using a stochastic approximation in an expectation-maximization technique on data relative to biomarkers.