  We set out to rederive the 8 Hubble parameter values obtained from estimated
relative galaxy ages by Simon et al. [Physical Review D, 71, 123001 (2005)]. We
find that to obtain the level of precision claimed in $H(z)$, unrealistically
small galaxy age uncertainties have to be assumed. Also, some parameter values
will be correlated. In our analysis we find that the uncertainties in the
Hubble parameter values are significantly larger when 8 independent $H(z)$ are
obtained using Monte Carlo sampling. Smaller uncertainties can be obtained
using Gaussian processes, but at the cost of strongly correlated results. We do
not obtain any useful constraints on the Hubble parameter from the galaxy data
employed.
