The size of the market is simply the summed turnover
of the companies since this figure represent the total
value of ITS goods and services provided after demand.
The companies’ selection—which companies can be regarded
as “ITS companies”—is then not an equally
straight-forward question. We created a set of criteria to
select the companies but some important firms were still
left out from the included group. This definition is identical
to the definition “the total market size is the total
value of sales”. The aggregate supply, i.e. the sales, of the
sector representing the size of the market relies on traditional
microeconomics concepts (see any standard microeconomics
text book, e.g. Eaton et al. [9] or Pindyck
and Rubinfeld [10])