Relating parameters in branching process and Smith-Martin models. Synthetic CFSE datasets were generated using the homogeneous Smith-Martin model with different division rates λ and μ = 0.2 day-1 and Δ = 12 hours. Each dataset contained the cell numbers in each generation at days 2 and 4. Branching process (BP) models were fitted to each. In all cases the best fit was provided by a homogeneous branching process with a timestep of 16 hours, as measured by the absolute value of the log likelihood. The QL estimates of the division probabilities γ are shown as diamonds, and the death probabilities α as triangles. Predicted values using the approximations – eqns (5) and (6) – are shown as solid lines.