S. E. Hinton’s story, “The Outsiders”, describes the ongoing conflicts between two social groups in an American high school, the “greasers”, who generally derive from lower class backgrounds, and the “socs” who derive from upper middle class backgrounds. The two groups differ not only in material goods but in style and manners. There is a double plot, one involving the ongoing conflicts between the two groups, and the other focussed on the love of a Greaser boy for a Soc girl. The main theme is that “despite their differences in habits and socio-economic background, the teens in both groups, share a common humanity.”
I think Cherry Valentine has the best thematic statement of the entire novel. She says the following in chapter 2.
Things are rough all over.
She's absolutely correct. Until Cherry tells Ponyboy the above statement, Ponyboy never really considered the Socs as people with problems. He just assumed that with all of their money and privilege, the Socs had it easy. Hinton does a great job through the novel of showing a theme of struggle among all of the teenagers in the story. Although, despite their antagonism toward each other, both groups are capable of displaying their humanity as well. This is absolutely shown when Ponyboy and Johnny risk their own lives to save the children from the burning church. Your statement could highlight the fact that despite having problems all over, the gangs and members are capable of great goodness.
If you don't like the similar struggles theme, you could write your statement about a different theme. I like the theme of loyalty. The book is about two gangs and the gang members. They would do anything for each other. That includes risking their lives for each other. Your statement could be something like "Loyalty is the glue that binds all of the characters together and motivates their actions throughout the story."