I think the most interesting thing that may be observable in this study would be children taken into care and offending. UK, Australian, and US research show that this is in fact the highest predictive factor (apart from being born) for future criminality, something that is studiously ignored!
Did the researchers actually compile and study the evidence behind this study, or did they once again have to depend upon the government department at the heart of this research, "arranging" the evidence for them (a problem incidentally that never pops up in discussion of the methodology- though surely has the largest 'margin' for error!!).
cheers