First, you need to include in the answer what traits you are referring to. Direct characterization is achieved when when the author, who is a 3rd person narrator, directly tells the reader what traits a character has. Indirect characterization is achieved when the thoughts, physical appearance, words, actions, and the reactions of others lead the reader to understand the character's traits. Of the two kinds of characterization, indirect is better. It allows a reader to "crawl into the skin" of a character and come to understand why he acts/reacts as he does. In the case of Bob Ewell, Harper Lee does not have to come out and say that he is a bad man. The words he speaks, his filthy appearance, and insolent manner allow us to reach our own conclusion about the kind of man he is. The actions of not sending his children to school and letting Mayella do all the work speak volumes to the reader. This man is low-life!