In this paper we describe a model of the distribution of alike elements in dialogical communication. Our starting point is the interactive approach to alignment which views priming as a basic mechanism of verbal interaction. As this mechanism predicts short distances of the occurrences of primes on the one hand primed units on the other we concentrate on the distance effect induced by priming. The present paper focuses on prerequisites of measuring this effect. Thus, it can be seen as a starting point of operationalising the notion of alignment in terms of information theory.