This paper shows the importance of comparing corpora that are really comparable. The paper conceives of texts as exemplars of situated genres and acknowledges that the rhetorical and discourse configuration of texts vary as a function of the contextual factors in which texts are situated. It argues that corpora may be considered equivalent (or similar to the maximum degree) across cultures to the extent that the text exemplars are similar in all of the relevant contextual factors. It concludes that cross-cultural corpora designs should attempt to control statistically as many of the relevant contextual factors as possible. If not, it may not be possible to say anything reliable about the possible effect of the language/culture factor on texts. Instead, possible differences found may be due to uncontrolled contextual variables.