Crispin Wright offers superassertibility as an anti-realist explication of truth. A statement is superassertible, roughly, if there is a state of information available which warrants it and it is warranted by all achievable enlargements of that state of information. However, it is argued, Wright fails to take account of the fact that many of our test procedures are not ‘sure fire’, even when applied under ideal conditions. An alternative conception of superassertibility is constructed to take this feature into account. However, it is then argued that when this revised concept of superassertibility is taken as the truth predicate of probability statements, statements whose test procedures are paradigmatically not sure fire, then any anti-realist theory of the sense of such probability statements cannot be compositional, in Dummett's sense of ‘compositional’.