This paper considers the viability and desirability of three aspects of formative assessment: peer assessment, self-assessment and evaluation, and their importance in the training of the professional interpreter. Even experienced student interpreters are often unaware of omissions, additions and misunderstandings in their own performances. When asked to assess themselves or each other, they frequently lack the analytical tools to be able to carry out such exercises. This paper is informed by educational practice in order to validate the use of these forms of assessment, and it demonstrates how student interpreters can use them to increase the amount of feedback they receive as they become professionals.