Researchers who look at four states where pot is legal find no evidence of negative outcomes. FALL RIVER, Mass. — We are either facing the end of the world or utopia, depending on whom you ask. Either way, both pro and con forces say life will change based on the vote for referendum question four, which asks if Massachusetts should legalize the recreational use of marijuana. Proponents say legal marijuana will raise tax revenue, reduce crime, stimulate the economy and improve public health. Opponents say legal marijuana will increase the use of alcohol and other drugs, increase crime, cause traffic accidents and cause teenagers to skip school. But Colorado, Oregon, Washington and Alaska say don’t worry about it.