We conducted coding interviews with 21 students from two R1 universities in the US to evaluate students’ secure programming practices. Our prior work showed that students lack skills and knowledge in five key themes contributing to security skills. To better understand how each theme contributes to the ability to write secure code, we designed a modified SOLO taxonomy for each of the five themes and used the taxonomy to evaluate students. Our assessment showed that most students have a simple understanding and skills of each theme. We also found that students who had pre-structural or uni-structural knowledge of these themes generally failed to write secure code and avoid security vulnerability, implying that there is a strong correlation between secure programming and these themes.