Moose is not particularly thrilled to move to Alcatraz Island because he shares the island with notorious convicts; therefore, a negative effect of the move is that he feels jumpy. In fact, he plans to sleep in his clothes so that he does not meet a convict while wearing his pajamas. Another negative effect of the move is that he has to move away from his old friends, which includes his best friend, Pete.
A positive result of his move is that his sister, Natalie, can attend the Esther P. Marinoff School, which his family hopes will help her (as she has autism). Moose wants his sister to get help, though he will miss her, so this is a positive effect of the move. In addition, moving is positive because Moose's dad has a solid job as an electrician at the prison. When Natalie leaves the island to attend school, Moose has more time to spend with his father.