Stats pages are a snapshot of the current status of the traditional
remailer network. They list the remailers the maintainer of that stats
page is "pinging", those remailers' capabilities and limitations, and
how well those remailers are replying to those pings. From this data,
remailer uptime and latency can be deduced.

Keep in mind that the results shown on different stats pages often
vary widely and that the stat page you are looking at shows the
results as seen from the remailer doing the pinging. Network
conditions between this remailer and the others can and will influence
the results.

For example, a stats source (pinger) temporarily without mail access
will list all pinged remailers as having low reliability (assuming
that Web access is present).  In fact, it is the pinger itself whose
reliability has declined.  Refreshing stats from such a pinger may
result in the remailer client complaining that there are not enough
remailers.

Other things that will influence the results are not having the
current key(s) for a remailer on the pinger's keyring.  Often key
changes are made and announced, but a stats page maintainer might miss
this, or his remailer isn't automatically updating with new keys and
purging old keys.  If possible (i.e., if the stats source provides
them), check the keyrings.

With new remailers coming on line all the time and others departing
the network after only a brief appearance, it can be very difficult to
maintain an accurate list of exactly which remailers are really
online.  Also, when a remailer joins or leaves the network, the uptime
and latency stats for that remailer will not respond instantaneously.
Stats are an analysis of data taken over several days and presented as
a moving average.
 
Some stats pages are in question 5.3.

Elcaro posts his Remailer Reliability Statistics daily in APAS. This
guy is a stats maniac! His stats offer:

* 1 Hop Remailer Check for a day and the last week 

* MultiHop(1-4) Remailer Check for a day 

* Position Check for the MultiHop Check for a day each remailer
  giving Success/Failure/Total/Percentage for every position 

* Position Check for the MultiHop Check Summary for the last week 

* Arc Analysis for Last 7 Days Success/Failure/Total/Percentage