Background: Studies on argument have found that participants tend to prefer explanations to evidence. This apparent bias toward explanation has been qualified recently by research that has found it to diminish with the availability of evidence. Aim: This study examines the use of explanation versus evidence in the context of argumentation with reference to the goals of particular argument situations. Sample: Seventy-nine eighth-grade pupils at a regular, urban middle school. Method: The pupils read argumentation scenarios, each having the stated goal of either explaining or proving a claim. The pupils rated the degree to which each of two provided assertions (one a theoretical explanation, and the other evidence-based) helped achieve the goal of the argument. On a second task, the pupils chose which of the two assertions should be more effective in achieving the argument goal. On the third task, the pupils generated either an explanation or evidence for each of the argumentation scenarios. Results: Pupils demonstrated sensitivity to the relative epistemic strength of explanation and evidence. They rated explanations as more advantageous in achieving the explanation goal, and evidence as more advantageous in achieving the proof goal. Conversely, however, when asked to generate or recall an explanation or evidence, pupils produced more explanations than evidence independent of the argumentation goal. Conclusions: The study refines the definition of argumentation context to include specific goals. Pupils were sensitive to the context of the argumentation situation (e.g.goals, availability of evidence). However, they appeared to have a disposition toward explanation when asked to produce an explanation or evidence-based justification.