The findings by a group of academic researchers at Columbia University paint a mixed picture of the United States nearly 50 years after Lyndon B. Johnson announced in his January 1964 State of the Union address that he would wage a war on poverty. They also contradict the official poverty rate, which suggests there has been no decline in the percentage of Americans experiencing poverty since then.

According to the new research, the safety net helped reduce the percentage of Americans in poverty from 26 percent in 1967 to 16 percent in 2012. The results were especially striking during the most recent economic downturn, when the poverty rate barely budged despite a massive increase in unemployment.

While the government has helped keep poverty at bay, the economy by itself has failed to improve the lives of the very poor over the past 50 years. Without taking into account the role of government policy, more Americans — 29 percent — would be in poverty today, compared with 27 percent in 1967.