Clans compete to obtain the most stars, as that is the first criteria
for rankings in the league. Aside from stars obtained normally, clans
will receive a 10-star bonus for winning a war.
During a League, anyone can view the standings of each clan in the League under
"Group", and also the scores of each war in "Rounds", including those
wars involving other clans.
Under the "Clan" tab, players can view the statistics of how each member in the roster performed so far in the
league, breaking down the number of stars collected by each member,
the total destruction accrued, and the number of attacks completed.
See here for more details