Calling when an all in bet is made

When an all-in bet is made one of the following conditions usually exists.
Case 1 -- The better is short stacked and the blinds are
going to over take his stack.
Case 2 -- The better has a made hand and wants to
shutdown play before someone draws a better hand.
Case 3 -- The better is bluffing.
Case 4 -- The better has the nuts (the best hand possible).

Case 1 - Will be fairly obvious and if the caller has a reasonable starting hand coupled with a large enough chip stack to absorb the all-in, the call should be made even if there are other callers. The object of the tournament is to eliminate players and the more callers the higher the chance the better will be eliminated.

Case 2 - Will be made to protect a better than average starting hand that has little chance of improvement and can be evaluated as a median pocket pair if made before the flop. If the bet is made after the flop its done to protect a low end straight or a low flush or in the case of very aggressive players a straight or flush draw. The flop must be evaluated for potential hands/draws. If the better has the nuts, the all-in bet would not be placed. The better will bet after the river and will make a value bet at the flop.

Case 3 - All-in bluffs are rare because of the danger of the better being eliminated however if the better has an overwhelming chip count to any remaining players in the hand it may well be a bluff. Calling with a made hand is a possibility.

Case 4 - Calling an all-in bet which requires commitment of all or most of your chips should only be done if there is reason to believe the caller holds the best hand. Calling on a draw should never be done except in Case 1