How can a winner be declared in the presidential race when not all of the precincts have reported?

I feel it is irresponsible to announce a winner before the polls are even closed or all of the precinct's have reported. Regardless of sides, the electoral votes should be withheld until all of the state's precinct's have reported. Then announce that state's winner. Looking at several of the new stations and websites all of them have different numbers and I have yet to see a state with more than 96% precincts reported and some of those that were awarded did not have ANY turned in. I am very disappointed by this election in the way results are reported by ALL of the media forums.