It is argued that policy makers, in government especially, use crude o
utput measures such as the link with performance to argue the case for
, or more often against, employee participation. The paper considers t
he problems associated with the use of such crude output measures but
argues that researchers cannot avoid the question of what impact parti
cipation has on organisational effectiveness. Data from a universal su
rvey of companies given in-depth assistance by ACAS are used to show t
hat, according to managers directly involved, a particular form of par
ticipation, the joint working party, has a strong positive benefit to
the organisation. This was true of both union and non-union firms. Thi
s has important policy implications.