Studies show an anecdotal correlation. Causation has never been shown.
Anecdotally, values in the black, impoverished community in the 1940s and 50s (among other time periods) were excellent. Particularly by comparison to current values in the impoverished community. (of any race)
Thomas Sowell has written several excellent books which cite this and much other evidence which lead to definitive proof that causation does not exist, only the casual, nebulous correlation to which many refer.
Determining "causation" is futile when the relationship is a self-pollinating Catch-22.
Trying to bury the problem with federal welfare dollars is not the answer.
Instead, barriers to private sector development, which would enable the people to pull themselves out of the quagmire, must be lifted.
Unfortunately, the Bush Administration has abandoned this conservative approach to salvaging our nation's urban centers. Instead, he undermines our domestic efforts with his agenda for economic globalization.