What are the similarities between the social structure in The Hunger Games and that of modern America?
One of the main similarities between Panem and the United States is the different levels of social class. Differences in social class are highlighted both in the day-to-day lives of the characters from District 12 vs. the Capitol and in the opportunity the children of those regions have for future success.
There's a stark contrast between the fashion-conscious citizens of the Capitol and the starving citizens of District 12. Citizens from the Capitol are concerned about appearances, while citizens from District 12 are struggling just to put food on the table. There are similar social and financial disparities in the U.S. today. Just pick up a tabloid to learn about what frivolous items celebrities are spending their millions on, while other Americans are homeless, unemployed, living on welfare, and just struggling to survive.
Similarly, children from a higher social class in Panem--children from the wealthy districts--stand a much better chance in the Hunger Games because they have the resources to train for the Games from birth. In fact, many tributes from those districts even volunteer to compete in the Games. Children from poorer districts (like District 12) are basically handed a death sentence when their names are called at "the Reaping." They're not prepared to compete and they almost always lose.
With the high tuition rates for college in America and the competition associated with the college application process, you can argue that children whose families can afford to send them to college and afford to give their children unique experiences that help them stand out on their applications have a better opportunity to earn a college degree than those whose families cannot. These children are more likely to succeed (like those from the wealthier districts are more likely to succeed in the Hunger Games) because they are afforded better opportunities from the start.