For example, a lower infant mortality rate than the United States.
Also, this is a statement about a relative change. What was the standard of living under Batista? Pretty bad unless you were one of the people who owned property or participated in the kleptocracy. There's a reason why Castro could gain the support required to overthrow that government in the first place.
Another thing to take into account is that similar countries fare much worse. Jamaica, Haiti, Dominican Republic, the countries that are somehow comparable to Cuba are worst in every imaginable way, even when they were not economically attacked for over 50 years by the biggest economic power in the world.
Also, this is a statement about a relative change. What was the standard of living under Batista? Pretty bad unless you were one of the people who owned property or participated in the kleptocracy. There's a reason why Castro could gain the support required to overthrow that government in the first place.