Baudisch 2011 Methods in Ecology and Evolution, The pace and shape of ageing

Baudisch 2011, The pace and shape of ageing.

Baudisch11 standardized survive curves by normalizing age by its own expectation:  x / E[x] . This is a very good idea and can be used to compare survive curves in different species with different time scale. For my work, it makes comparing yeast replicative and chronological lifespan possible.

Baudisch11 argues that 'shape' is a unit-less measure, and 'pace' is basically 'rate' with unit 1/time.
Shape measures discussed are:
Omega/L (Omega is age at 1% viability, and L is the average age).
mu(Omega) / mu(0) or \bar{mu}
mu(L)/mu(0) or \bar{mu}

Pace measures argued by Baudisch11 seem to include the two canonical Gompertz parameters.
In its Figure 3, L, Omega, and Maturity seem to be considered as 'pace' measures, too.

Baudisch11 uses 'mortality' for 'mortality rate', which can be seen in her description of the Gompertz model.

Baudisch11 discussed a measure proposed by Ricklef1998 and argued that it is problematic.

It can be seen that x/E[x] is unitless. So, Baudisch11 approach is  a nondimensionalization treatment.
Baudisch11 discussed some previous work on dimensionless analysis of aging: Pearl and Miner 1935, Eakin 1994.

Numerically, it is straightforward to calculate the 'shape' measures. However, it is not straightforward to find the analytic form of the shape measures based on the Gompertz or Weibull models.

The median lifespan, i.e., the 50% quantile, has a analytic solution. So, normalization by the median lifespan can be used for both theoretical and empirical analysis.