Hi.
I’m Karen McKee with another video about scientific writing.
Someone recently wrote to me asking about where in a paper to put the rationale for
the scientific approach, in particular information about the selected study site.
In the methods or in the introduction?
What we’re talking about is a statement justifying the approach taken in a study.
Why did you select a particular study site?
Experimental design?
Organism?
Or analytical technique?
These are questions that reviewers and readers will be asking as they read your paper.
So it makes sense to provide answers.
Generally, such a statement would appear in the introduction after you state the purpose
of the research.
For example, if your study took place in a unique or important setting, you would want
to point this out in the introduction to add to the merit of your research.
This might be a major river delta, an active volcano, a rare plant community, or a moon
of Jupiter.
Details about the study site would be given in the materials and methods section, not
the introduction.
Similarly, if you used a novel technique that was key to the study outcome, you might briefly
describe it in the introduction and explain why it's better than other techniques.
Although you can explain the rationale for the scientific approach in the methods section,
highlighting such information in the introduction contributes to the overall impression of the
importance of your work.
But exactly how should such a rationale be worded, how long should it be, and where should
it go in the introduction?
Let’s take a look at some specific examples.
First, an example that explains the rationale for using a particular study site.
This paper reported on a study of how mangroves accumulate organic matter, which helps them
to keep pace with rising sea level.
The last paragraph of the introduction explains the advantages of the selected study sites.
The chosen sites in Belize were not only representative of peat-forming forests in the wider Caribbean
Region they were also relatively undisturbed by human activity.
We also mentioned additional study sites in Honduras and Panama and other locations, which
tells the reader something about our scope of inference.
Specific details about the sites were given in the methods section.
Now, the rationale for the selected study site need not be lengthy.
In this paper, a single sentence said that the hypotheses were tested at a long-term
study site.
If you work in an important geographic location or study a major event, that information is
important to your rationale.
In this example, we worked in a major delta system, the Mississippi River Delta, and studied
the effect of two major hurricanes on sedimentation.
Information about both the importance of the location and the hurricane events was given
in multiple places throughout the introduction.
In this paragraph, for example, we explained how our choices would aid in understanding
how future vegetation shifts would affect vulnerability of the delta to rising sea level.
In the last paragraph, we said that in addition to a field survey of hurricane sedimentation,
we would analyze data from a regional network of long-term study sites.
In providing these statements, we told the reader that not only was our study worthwhile,
but our approach was well thought out.
If you don’t have a field study, you might instead highlight a novel experimental approach
or a special experimental facility in the introduction.
In this paper, we wrote a fairly lengthy rationale for the mesocosm approach and experimental
facility that we used to assess responses of salt marsh and mangrove vegetation to CO2
enrichment.
This description came after the list of questions we posed in the introduction.
It explained to the reader some of the reasoning behind our approach, which might otherwise
not be apparent.
If you use a special analytical method or protocol, you might want to explain in the
introduction why it was used in your study.
In this paper, for example, we used stable isotopes to study nutrient limitation.
Several paragraphs at the end of the introduction described how stable isotopes can be used
to assess nutrient sources, biological transformations, and stress factors affecting plant growth.
This brief description told the reader why we took that particular approach, which prepared
them for details about the technique in the methods.
You might also use a new or unique statistical test or modeling method.
In this paper we used a statistical method called structural equation modeling or SEM.
At the end of the introduction, we explained why SEM was used and how it aided interpretation
of our data.
In the methods, we provided further rationale for this approach as well as details about
SEM protocols.
A final rationale I’ll mention is description of the organism studied and why it was selected
for investigation.
In this paper, for example, we explained that although many studies had examined root metabolism
in response to flooding in a number of plant species, little was known at that time about
mangrove root metabolism.
We provided a brief description of where mangroves grow and suggested that their study would
provide key insights about metabolic adaptation of plants to flooded soils.
Those are just a few examples of how the rationale for a scientific approach can be used in the
introduction.
I should point out, however, that you need to carefully consider what aspects of your
approach to highlight in the introduction.
For example, highlighting a study site that is not particularly important or not representative
may make your paper sound too parochial and not of wide interest to a journal’s readership.
Now, it’s perfectly fine to justify why you did something a particular way in the
methods section.
In this paper, for example, several procedures are justified with a brief explanation in
the methods.
You can pause the video to read these highlighted sections.
To summarize, including a statement in the introduction that provides a rationale for
the approach you took can add to the overall merit of the study.
This rationale usually follows the statement of purpose or list of questions or hypotheses
addressed but doesn’t have to.
Obviously, what you highlight will vary from study to study.
To make this decision, you can ask yourself these three questions.
Do I need to explain why I took a particular approach?
Will that rationale add to the overall impression that my study is worthwhile and feasible?
Does the rationale work in the introduction or should it go in the methods?
Thanks for watching and don’t forget to like my video if you found this information
useful.