  Factors driving success and failure in CS1 are the subject of much study but
less so for CS2. This paper investigates the transition from CS1 to CS2 in
search of leading indicators of success in CS2. Both CS1 and CS2 at the
University of North Carolina Wilmington (UNCW) are taught in Python with annual
enrollments of 300 and 150 respectively. In this paper, we report on the
following research questions: 1) Are CS1 grades indicators of CS2 grades? 2)
Does a quantitative relationship exist between CS2 course grade and a modified
version of the SCS1 concept inventory? 3) What are the most challenging aspects
of CS2, and how well does CS1 prepare students for CS2 from the student's
perspective? We provide a quantitative analysis of 2300 CS1 and CS2 course
grades from 2013--2019. In Spring 2019, we administered a modified version of
the SCS1 concept inventory to 44 students in the first week of CS2. Further, 69
students completed an exit questionnaire at the conclusion of CS2 to gain
qualitative student feedback on their challenges in CS2 and on how well CS1
prepared them for CS2. We find that 56% of students' grades were lower in CS2
than CS1, 18% improved their grades, and 26% earned the same grade. Of the
changes, 62% were within one grade point. We find a statistically significant
correlation between the modified SCS1 score and CS2 grade points. Students
identify linked lists and class/object concepts among the most challenging.
Student feedback on CS2 challenges and the adequacy of their CS1 preparations
identify possible avenues for improving the CS1-CS2 transition.
