119 / 274
臺大管理論叢
第
27
卷第
3
期
119
Prior Exploration
. Because of the semiconductor industry’s technological continuity,
we assumed that one firm’s exploration in the sequence of investments would be dependent
on what other firms were doing. We therefore defined prior exploration for this study as the
aggregation
of previous individual firms’ exploratory investments. We applied a lag structure
methodology to a longitudinal dataset to model prior exploration to determine how these
prior explorations affected exploitation and performance.
Uncertainty
. Given that this study focuses on a single industry—the semiconductor
industry, uncertainty was identified mainly as firm-specific uncertainty (Beckman et al.,
2004). Following Beckman et al. (2004), this study used the standardized monthly volatility
of the focal firm’s stock price to measure firm-specific uncertainty. The monthly volatility is
calculated as the coefficient of variation for firm j’s annual monthly stock closing price and
was collected from the CRSP database.
Standard Deviation (Firmʼs Monthly Closing Price, Year
i
, Firm
j
)
Average (Firmʼs Monthly Closing Price, Year
i
, Firm
j
)
where
i
= 1988, …, 2005
3.3 Control Variables
We included several control variables to account for industry and firm characteristics
that could influence the relationships among exploration, exploitation and performance.
Size and age
. Large firms tend to exhibit economies of scale (Sorenson, McEvily, Ren,
and Roy, 2006). The firm age affect permits rapid adaptation to new technologies (Sørensen
and Stuart, 2000). Thus, we added these two control variables to our regression analysis. We
used the logarithm of net sales as our measure of a firm’s size and we calculated its age by
subtracting the founding year from the year to be analyzed.
Current ratio and debt/equity ratio leverage
. The current ratio is defined as the ratio
of current assets to current liabilities. The debt/equity ratio was defined as the long-term debt
divided by total equity. These two ratios were used as the respective measures for the short-
term and long-term financial resources available for allocation to exploration and
exploitation.
Industry growth and concentration
. Because an industry’s growth and concentration
have been found to be important control variables in studies of firms’ performance, we
included these variables in this study. Industry growth was defined as the yearly growth rate