JoomlaStats can be activated by using mod_jstats_activation or by putting activation code into the template (see FAQ How to Activate JoomlaStats?).
There are 2 different aproaches to place the activation module/code:
1) at the beginning (visitor will be able to see his entry)
2) at the end (the best performance)
We'll further explain by giving an example:
We have installed the activation module and module Flags (mod_jstats_flags).
If module activation will be placed before module flags, the visitor will see his entry in module flags. If activation module/code will be after module flags, visitor will not see his entry, because his entry will be counted later - by module activation.
Sometimes it's possible to put the activation module/code after the body close tag (</BODY>) or even after (</HTML>) tag (in the template). Because the site's information is presented to the visitor before logging statistics, this is the best solution if performance is very important to you.