This paper looks at students' responses to two concept questions: one on equilibrium and one on equivalence, which is an equilibrium problem from a different perspective. Student responses were from final exam questions that included explanations and from national Statics Concept Inventory (SCI) data. Examination of students' explanations to these two questions shows that students are not consistent in their assessment of force and moment equilibrium, and a mapping of the explanations onto the answer distributions implies the same result is true for the national SCI data. The conclusion of this study is that most students are influenced by context when assessing equilibrium.