Control Variables
We performed separate regressions for each of the
18 measures of organizational performance serving
as the dependent variable. Using the SMALLREG
category as the comparison group, we entered a
number of control variables to effectively capture
other organizational and environmental factors that
are related to both the adoption of HRM practices
and the perception of organizational performance.
We selected control variables on the basis of their
potential to explain some of the variance in our
dependent variable. We believed that organizational
size and percentage of unionization had the poten-
HOSPITAL TOPICS: Research and Perspectives on Healthcare
tial to explain some of this variance, and therefore
they needed to be controlled for.
To capture size effects, we included the natural
log of the number of employees in the organization.
Because the extent of unionization may affect
the effectiveness of the organization or perceptions
of its performance, we entered an estimate of the
percentage of unionization of the workforce.