Yes, the catchment area undoubtedly has a huge effect.  It was to late to edit when I though to mention that.

I disagree that poor (financially) parents are bad parents.  I think it is poverty of expectation which is the real blight on children.  There are parents who have little money and had few opportunities themselves who devote time and resources to their children's education and wellbeing.  Maybe what is most important for any child is the degree to which their parents are prepared to make sacrifices for their child.