Causes of Poverty

I have often seen the claim made that 90% of poor adults:

1. Dropped out of high school.

2. Had children out of wedlock.

This doesn't seem implausible to me.  Does anyone know if there is some study from which this comes?

From a social advocacy group:

6. A higher percentage of young adults (31%) without a high school diploma live in poverty, compared to the 24% of young people who finished high school.

From UC Davis:

The Census Bureau reports poverty rates by educational attainment for people aged 25 and older. In 2014, the overall poverty rate for people aged 25 and older was 12%.
The poverty rates by work experience for that age group ranged from 5% to 29%.
5% for people with a bachelor’s degree or higher
10%for people with some college but no degree
14% for people with a high school diploma and no college
29% for people with no high school diploma

That's impressive.  Dropout alone is a big factor.

Brookings Institute:

Since 1970, out-of-wedlock birth rates have soared. In 1965, 24 percent of black infants and 3.1 percent of white infants were born to single mothers. By 1990 the rates had risen to 64 percent for black infants, 18 percent for whites. Every year about one million more children are born into fatherless families.

The same paper argues that Roe v. Wade played a big part in increasing these births:

Since 1969, however, shotgun marriage has gradually disappeared (see table 1). For whites, in particular, the shotgun marriage rate began its decline at almost the same time as the reproductive technology shock. And the disappearance of shotgun marriages has contributed heavily to the rise in the out-of-wedlock birth rate for both white and black women. In fact, about 75 percent of the increase in the white out-of-wedlock first-birth rate, and about 60 percent of the black increase, between 1965 and 1990 is directly attributable to the decline in shotgun marriages. If the shotgun marriage rate had remained steady from 1965 to 1990, white out-of-wedlock births would have risen only 25 percent as much as they have. Black out-of-wedlock births would have increased only 40 percent as much.