To extend the existing research examining multiple text comprehension and its assessment, we developed a verification task approach to assessing of information that was "explicitly" and "implicitly" presented "within" and across nine texts. A nonparametric form of signal detection theory was used to analyse the performance of 47 middle school students using a rating response scale to judge the truth value of specific statements. The results showed that the four types of statements in the verification task (explicit and implicit; within- and across- text) behaved systematically: within-text explicit statements were the easiest for students to verify as true and across-text implicit statements were the most difficult. Practical implications of these results regarding assessment of complex comprehension processes are discussed.