BJ Torunament Question...

Playin in my first BJ Tournament this weekend in Reno...I read SW's Casino Tournament Strategy book sometime back, (a tough read for this meager brain) ... He talks about determining the amount of winnings it would take to to be certain to advance to the next round. My question, if anyone knows.. Is this "amount" a function of of how the round is progressing, or is there some kind of formula that can determine from the start how much would give you the best chance of advancing to the next round? Based on the "buy in" amount maybe??