The state of research and practice in EPSM is in constant flux.
As with most research, the data collected is a snapshot at a point
in time. In our sample, corporate reports spanned from 2005 to
2009 as these reports are not always published each year, or on a
regular schedule. The literature was examined through the end of
2011. New corporate reports and papers come out constantly, and
our data may not capture all recent trends. There is a significant
lag in reporting and publishing that also makes data less timely.
For example, as oil prices rose rapidly and then fluctuated, many
firms expressed an interest in using less oil, which also has a
significant environmental benefit. In addition, the recession of
2008–mid 2010 may have temporarily slowed firms’ environmental
efforts, though the popular press indicates otherwise
(Wheeland, 2012). In general, the differences in the different
collection dates seemed to have no impact on the results.
The data regarding the environmental practices has several
limitations. First, we cannot assume that corporate reports are
fully reflective of everything that is going on in the company
related to EPSM. Certain practices may be kept as proprietary, or
deemed not interesting, or simply not known about in corporate
headquarters. Further, there is no requirement that these reports
be audited, and the reporting standards (Global Reporting Initiative)
are voluntary. Additionally, our interpretation of the data
has validity risks, as any content analysis approach does. We have
attempted to address those risks through using multiple coders and a standard protocol for enhancing validity and reliability in
qualitative research.