Studies of poverty are notoriously shoddy. Cross-country studies are especially problematic. If you look at just the U.S., the poverty rate was declining until LBJ’s war on poverty. Take a look at the work at the Independent Institute:
Charles Murray made this point in his book, Losing Ground.
Thomas Sowell has done some good work on poverty. Take a look at his book, Poverty, Wealth, and Politics:
Here Sowell points out that market reforms have lifted hundreds of millions of people out of poverty in China in the last three decades:
http://www.realclearpolitics.com/Commentary/com-1_10_06_TS.html
Henry Hazlitt wrote an entire book on that point:
https://mises.org/library/conquest-poverty
Here is a Mises Institute wiki on poverty:
http://wiki.mises.org/wiki/Poverty
Here’s a recent Mises Daily article:
https://mises.org/library/freedom-global-poverty-and-failure-foreign-aid
Another point is that private charity actually works to reduce poverty whereas government programs do not. Here is Michael Tanner:
http://www.cato.org/publications/commentary/more-welfare-more-poverty
Marvin Olasky has written about this as well:
http://www.amazon.com/Tragedy-American-Compassion-Marvin-Olasky/dp/089526725X