The paper at hand deals with morphological marking of information structural relations from the perspective of North-Western Siberian languages. Given many items (morphemes as well as particles and clitics) which have been analyzed as markers of information structure in these languages, I try to discuss whether they indeed mark information structural relations or whether this supposed marking is rather a side effect of other functions expressed. In order to develop criteria for decision marking, I rely on the concepts of sufficiency as well as necessity and sufficient as well as necessary conditions, respectively. Additionally, I argue that the latter can be arranged hierarchically with respect to their reliability for the evaluation of potential markers of information structure, being intertwined with functional and transparency coding principles.