study of red****rting (late entrance to kndergarten)

NBER has a new study on the effects of red****rting. The abstract is at
http://papers.nber.org/papers/w14124
and the full paper at
http://www.nber.org/~dynarski/Deming_Dynarski_Childhood.pdf
. Overall
the authors appear negative about it:

"We show that the decreased grade attainment of six-year-olds
reverberates well beyond the kindergarten classroom. Recent stagnation
in the high school and college completion rates of young people is
partly explained by their later start in primary school. The
relatively late start of boys in primary school explains a small but
significant ****tion of the rising gender gaps in high school
graduation and college completion. Increases in the age of legal
school entry intensify socioeconomic differences in educational
attainment, since lower-income children are at greater risk of
dropping out of school when they reach the legal age of school exit."