The Decline of Seasonality in Australian Quarterly Aggregate Strike Statistics: 1983-2003

This paper investigates the changing pattern of seasonal influences on quarterly Australian data on aggregate working days lost due to industrial disputes per thousand employees for the period 1983:1 to 2004:3. The analysis suggests the presence of (a) a structural break in the stationarity properties of the data around 1992-93 and (b) the presence of seasonality in the data, though this appears to be largely confined to the pre-1993 period. It is noted that the break in the stationarity and change in seasonality properties of the data corresponds approximately with the period between the introduction of enterprise bargaining in the Australian Industrial Relations Commission in late 1991 and the introduction of the Industrial Relations Reform Act 1993, which was enacted in early 1994. It is suggested that these and other legislative and socio-economic changes that ushered in the progressive abandonment of centralised wage-fixing practices, may have contributed to the near elimination of seasonality in aggregate quarterly strike statistics during the latter part of the period under review.