*42%*:**Student Objections to and Understanding of Non-Cartesian Unit Vector Notation in Upper-Level E&M***35%*:**Improving Student Understanding of Vector Fields in Junior-Level E&M***32%*:**Students' difficulties with unit vectors and scalar multiplication of a vector***30%*:**Longer term impacts of transformed courses on student conceptual understanding of E&M***28%*:**Vector Addition: Effect of the Context and Position of the Vectors***27%*:**Contrasts in Student Understanding of Simple E&M Questions in Two Countries***27%*:**Peaks and decays of student knowledge in an introductory E&M course***25%*:**Tapping into Juniorsâ€™ Understanding of E&M: The Colorado Upper-Division Electrostatics (CUE) Diagnostic***25%*:**Validation of a Conceptual Assessment Tool in E&M II***25%*:**Student difficulties with quantum states while translating state vectors in Dirac notation to wave functions in position and momentum representations***25%*:**Student understanding of unit vectors and coordinate systems beyond cartesian coordinates in upper division physics courses***25%*:**Improving student understanding of Dirac notation by using analogical reasoning in the context of a three-dimensional vector space***24%*:**Graphical representations of vector functions in upper-division E&M***24%*:**Testing Studentsâ€™ Understanding of Vector Concepts***23%*:**Test of understanding of vectors: A reliable multiple-choice vector concept test***23%*:**Research-Based Course Materials and Assessments for Upper-Division Electrodynamics (E&M II)***21%*:**SEI: Junior E&M I Course Materials - Student Difficulties***21%*:**Maximum Likelihood Estimation (MLE) of studentsâ€™ understanding of vector subtraction***21%*:**Students as Co-creators: the Development of Student Learning Networks in PeerWise**