How did Gatsby measure the success of his party in "The Great Gatsby"?
The only reason Gatsby hosted such lavish parties was to attract the attention of Daisy Buchanan. He did not care who else came, as witnessed by the fact that he was hardly ever seen at his own parties and he allowed anyone in to the celebrations. Once he has met Daisy again, and she visits one of his parties, she hates it. Then the parties stop, and Gatsby even dismisses his servants so there won't be any gossip about her afternoon visits. Obviously, none of his parties were a real success, because none of them ever attracted the object of Gatsby's obsession, Daisy.
Gatsby's parties serve to give him name recognition.
Gatsby's notoriety, spread about by the hundreds who had accepted his hospitality and so become authorities upon his past, had increased all summer until he fell just short of being news.
The rumors that abound about him are "a source of satisfaction to James Gatz of North Dakota." Gatsby's desires notoriety; he wants people to know his name, a name he has had "ready for a long time," Nick notes. It is this very conception of himself to which Gatsby is faithful. These rumors provide Gatsby a promise of notoriety that will, perhaps, draw the attention of those whose notice he seeks. This is his American Dream, a dream in which material values are bound to imagination. Thus, the concept of Jay Gatsby has been filled in by the imaginations of others and given the "substantiality of a man." With his now famous parties, Jay Gatsby has made a name for himself, one he hopes will compete with the name of Tom Buchanan.
Once he draws the attention of Daisy Buchanan, Gatsby feels his parties have served his purpose and he stops them so that no one will know that Daisy has come to his house.