in fact, in case of political economic cooperation, they are separated into many levels.
starting with the "loose cooperation" ,it is the integration caused by the same identity, similarly culture, languages to make the common sense among members.
the next level is the "league", which is more intensive than previous form.
in this level,you can find an organization or institution that is newly formed for linking members together,such as arab league.
the next step is the "association" which is more intensive than league.