Environmental Engineering Reference
In-Depth Information
evidence in support of competing hypotheses, (11) interpret and provide context of
results and make appropriate inference of results and conclusions, and (12) publica-
tion of results in a peer-reviewed outlet. Individual investigators can insert the details
specific to their study within these broad steps to initially design a study.
Without study design, the scientific method would be ineffective as a means to
attain reliable knowledge. Investigators must be aware that study design, as well as
experimental design, statistical analyses, and data modeling, should not be consid-
ered a “cookbook” process devoid of critical thought. Once a wetland-related
question has been formulated and competing hypotheses developed, there are
usually a number of different approaches to appropriately design a study that can
be used to accumulate evidence to test one (or more) hypotheses. Furthermore,
development of a study design must be considered in the context of accessibility of
study sites, equipment and labor costs, time to collect samples, other time-sensitive
constraints (e.g., lab availability, sample storage, and occurrence of measurable
dependent variables), and a multitude of other potential considerations. In addition,
it is important to realize that it common for changes in the design to occur after a
study has been implemented. Hopefully, if one is unfamiliar with the wetland type
or study question, limitations of or changes to a study design can be addressed using
prior knowledge (e.g., experience of the investigator, literature or previously
collected data). Without such insight, the initial study effort is typically defined
by determining the limitations of the proposed design and, at times, resulting in a
potentially unreliable data set. As these issues may compromise acquisition of
reliable knowledge, it is recommended that any proposed study design be reviewed
by a biometrician or statistician familiar with the inherent quantitative hurdles
associated with natural systems and an investigator familiar with the wetland type
or issue proposed for study.
1.3 Development of a Study Hypothesis
Reliance on ecological theory and generation of hypotheses are basic to study
design. A
theory
as defined for the purpose of study design is a “broad, general
conjecture about a process” (Romesburg
1981
: 295) or “a conceptual framework
through which the world is observed and facts about the world are discerned”
(Williams
1997
: 1009). A
hypothesis
is a proposed explanation for a process or
phenomenon that creates data. Once an intangible theory has been developed
relative to an observed phenomenon, hypotheses can be formulated to describe
the natural processes that produced the phenomenon that lead to predictions of
outcomes should the hypotheses be true. Development of hypotheses is the key step
for a successful study design. Without sound, well-developed, hypotheses, it is
difficult to conduct an investigation that will result in clear conclusions and advance
our understanding of ecological systems.
Hypotheses follow the question being asked and must be explicitly stated so as to
provide predictive power or specific conditions under which the hypothesis is true.
