(Table 1)
The overall change in the number of plants is the net result of plant
entry and exit. We summarise in Table 2 the entry pattern of foreign-
owned plants into the Irish manufacturing sector over the period 1980-
1996. A mean annual entry rate is calculated using methodology outlined
in Strobl et al (1998) and originally in Davis and Haltiwanger (1990).
The plant population size is defined in the manufacturing sector as
P + P
E Et Et -1
Et
(1)
2
where PEt is the number of plants in category12 E at time t and aEt is the
average number of plants in this category over the period t-1 to t. The
number of births is calculated as the number of plants alive in category E
in time t that were not alive in category E in time t-1. The birth rate is
defined as follows:
Et
bEt
aEt
(2)
BEt , the birth rate, is a measure of the extent of entry into an industry
(1980-1996). Over this period, there was a mean annual birth rate for all
plants of 4.6 per cent. Disaggregating these plants by sector, we find that
the mean annual entry rate in the high-tech sector is significantly higher
than those in the less technologically-sophisticated sectors.
12 Examples of these categories could be sector, age category or size category.