  The 2008 economic crisis was not forecastable by at that time existing models
of macroeconomics. Thus macroeconomics needs new tools. We introduce a model
based on National Accounts that shows how macroeconomic sectors are
interconnected. These connections explain the spread of business cycles from
one industry to another and from financial sector to the real economy. These
lingages cannot be explained by General Equilibrium type of models. Our model
describes the real part of National Accounts (NA) of an economy. The accounts
are presented in the form of a money flow diagram between the following
macro-sectors: Non-financial firms, financial firms, households, government,
and rest of the world. The model contains all main items in NA and the
corresponding simulation model creates time paths for 59 key macroeconomic
quantities for an unlimited future. Finnish data of NA from time period
1975-2012 is used in calibrating the parameters of the model, and the model
follows the historical data with sufficient accuracy. Our study serves as a
basis for systems analytic macro-models that can explain the positive and
negative feed-backs in the production system of an economy. These feed-backs
are born from interactions between economic units and between real and
financial markets. JEL E01, E10.
  Key words: Stock-Flow Models, National Accounts, Simulation model.
