This paper is interested in the modelling of the relationship between
active and passive labour market policies and the aggregate unemployme
nt outflow rate. Our model is based on a matching function and include
s a simple representation of the competition between various groups of
job searchers. The empirical analysis uses Belgian data. Faced with v
ariables that are often integrated of order 1 according to the usual t
ests but which cannot strictly speaking be integrated, we contribute t
o an important methodological debate by comparing the conclusions of a
classical econometric analysis and a cointegration approach.