  In high energy particle collisions the shape of the event, i.e. the relative
distribution of particles in momentum space, is often used to try to select
events with certain topologies. It is claimed that an event shape observable
like transverse sphericity is able to discriminate between jet-like events and
events that are dominated by soft production from the underlying event.
  In this paper we investigate the relationship between the shape of the event
and the number of jets found in the respective event for both $e^{+}e^{-}$ and
pp collisions using the PYTHIA model. In $e^{+}e^{-}$ collisions, we find that
the transverse sphericity of the event can be used effectively to either
enhance or suppress the fraction of jets found in the selected sample, and can
even discriminate between single, two, and multi-jet topologies. However,
contrary to current literature, we find that in pp collisions this does not
hold. It is shown that the transverse sphericity as well as the particle
multiplicity is sensitive to the number of multi-parton interactions.
