\section*{Results}
\subsection*{Temporal debasement and cross-disciplinary bias of current
measures} In Figure 1, we illustrate the temporal debasement of
the \textit{m}-quotient, defined as $h/y$, where $y$ is the number of years since a scholar's
first publication. Astronomers who began their career in the
1950's have systematically lower \textit{m}s than those who started
their career later on. The red line in Figure 1 is an
exponential best-fit regression line with slope $b=0.0314$ and a
$0.95$ confidence interval band. Year means are plotted as filled
black circles. In 50 years, the average \textit{m}-quotient has
increased from $0.28$ to $1.62$, with an increase rate of $3.1$\% per
year, and well above the global mean of $x = 0.855$.  (We also run an
identical regression analysis on a cohort of 697 astronomers for whom
we have access to both publication record \textit{and}
Ph.D. dissertation. Using the doctoral graduation year as the starting
point of their career we find similar effects of temporal debasement
--- best-fit regression line has slope $b=0.027$.)

In Figure 2 we show cross-disciplinary bias of the
astronomers working in different fields of specialization is displayed as a box-and-whisker
plot. Astronomers' fields of specialization are computed by
simply selecting the single most recurrent keyword used by authors in
their published articles. In order to isolate disciplinary effects, we
only analyze a subset of the corpus which includes $1601$ astronomers
who started their career in the 1990s and who publish in popular
sub-disciplines in this time window (fields with 30 authors or less
are excluded from this analysis). 
The dashed line in Figure 2 shows the global
mean \textit{m}-quotient for all authors in the corpus
($x=0.855$). 
We find that for only a small
portion of sub-disciplines (6 out of 23) does the global mean {\it
m}-quotient fall within the discipline-specific upper or lower
quartiles (``atmosphere'' through ``planets and
satellites''). Astronomers who publish in all the other fields have
systematically higher \textit{m}-quotients than the global average, as evinced by higher median \textit{m}-quotients for fields ``gravitational waves'' to ``galaxies evolution''.

Differences so large across time and disciplines make comparison of
individuals, such as in promotion and tenure decisions, quite
difficult.  Over time, a 3.1\% yearly productivity measure inflation
causes a difference of $2.5$ in \textit{m}-quotient between average 40
year olds and average 65 year olds.  With differences among
sub-disciplines also a factor of two or more, independent of age, we
suggest that citation counts and derived measures such as \textit{h}
and \textit{m} should not be used, except for crude evaluations of
scholars' impact.


