  Decomposition is the basis of works dedicated to business process modelling
at the stage of information and management systems analysis and design. The
article shows that the business process decomposition can be represented as a
Galton Watson branching stochastic process. This representation allows
estimating the decomposition tree depth and the total amount of its elements,
as well as explaining the empirical requirement for the business function
decomposition (not more than 7 elements). The problem is deemed relevant as the
obtained results allow objectively estimating the labor input in business
process modelling.
