Doubling Time

Doubling time is an important concept in many life sciences and in epidemiology, in particular: It refers to the length of time required for some quantity to double in size. It is commonly used to refer to human population size, but it is also used to describe, for instance, growth of viral counts or antigens, tumors, and the number of cases of a particular disease. Suppose we have a quantity Q(t) growing in time t. The function Q(t) may stand for the population size or the amount of a substance at time t. Doubling time is the time it takes for Q(t) to double in size and is uniquely determined by the growth rate r(t). If Q(t) has an exponential growth, then the doubling time ...