I concur that poverty plays a strong role in determining how kids perform in school. However, culture is very important too. I use the term Hispanic to refer to Mexico all the way down because we do have a large central american poplulation. The Hispanics don't seem to value upper level education very much. They want their kids to do well in life, but to them if their son goes on to own a landscape business, he is successful. In other words, they don't see white collar jobs as the be all.
Also, I think the Hispanics, particulary the first generation, suffer from low self esteem. I tutored a foster kid in Santa Ana for two years. His mother was druggie in and out of prison and he lived with the great aunt and uncle. They were great people, but couldn't seem to get him to connect with his school work so they contacted the YMCA.
He was just entering the 6th grade and reading at the 2nd grade level. On our first meeting I realized the kid wasn't stupid, but he thought he was so he didn't try. He was very into sports, so I started brining the LA Times sports page to our sessions. He was also into rap music, so I would burn CD's that had edited songs and have him write the lyrics. His reading skills progressed so rapidly and he started taking an interest in school. Feeling that maybe he wasn't dumb after all, he started to engage more with his teacher and getting good grades was something he could do. 6 months later he was reading at his grade level and a year later a year ahead.
I'd like to say that the story ended happily, but it didn't. His mom got out of jail, his brother went in and mom started coming around. She'd make promises that she inevitably would break. No coincidence here, but he started hanging around a new group of kids who were a bad influence. He always had this "do we have to do this" attitude, but once we got started everything was fine, but that started to change. I'd show up at 10:00 am on Saturday and his eyes were fire red because he was stoned. I called him on it, he denied it and just got so darn stubborn that I called it quits.