Download Are you improving a method?

How to write the introduction
Lecture Outline
1. Function of Introduction
2. Length
3. Parts
4. Examples
Introduction Function
Motivate the reader!
Introduction
Methods
Results
Discussion
In hopes they will read the
entire paper
THROUGH the discussion
Intro
Function
•
Why did you do this study?
•
How does it compare to what is currently
accepted?
•
How are you going to do the study?
•
Short summary of what you found
= your main point (not in every journal)
Ref: V. McMillan
Why did you do it?
• Are you testing a hypothesis?
– Do people who have had hepatitis B virus have a
higher incidence of hepatitis C virus compared
with people who have not had a HBV infection?
• Are you improving a method?
– Faster, cheaper, more sensitive
• Are you performing a descriptive study?
– Characterizing the distribution of dengue viral
infection by geographic region
Length
•
Keep it BRIEF
•
See your target journal for average
length of introduction
•
Try to limit the introduction to 3 or 5
paragraphs
Introduction
Methods
Results
Discussion
Let’s dissect the
introduction into
parts.
Flow of Introduction
General
Specific
Ref: M. Zeiger
Flow of Introduction
Known
Unknown
Question
Approach
Structure your paragraphs
First paragraph
1. Very broad and general
2. Orients reader to importance of topic
First sentence
• “Mycobacterium tuberculosis is the causative
organism of tuberculosis (TB) and produces
8 million new cases of TB annually.”
• “Dengue fever and its more severe form,
dengue hemorrhagic fever/dengue shock
syndrome, are considered among the most
important and widespread reemerging
infectious diseases in developing
countries.”
Relationship to other studies
1. Summarize previous knowledge
2. Prepare the scene for your work
• Reveal gaps and holes
• Raise a question
Cite relevant studies ONLY!
–
Make sure you have done your literature
review.
–
DO NOT summarize your entire field!
–
However DO reference studies that helped
you come up with YOUR question.
State your question
• What specific hypothesis are you testing?
• What exact process are you describing?
• What method are you trying to improve?
How did you do study?
• BRIEFLY say this in 1 or 2 sentences.
Examples- “In this study, we characterized M.
tuberculosis genotypes in Delhi using DNA
fingerprinting and oligotyping.”
- “We assessed the prevalence of Hepatitis A virus in
storm drains by RT-PCR.”
Known
Unknown
Q
A
Introduction
Hypothesis Paper Model
Known:
YY is very important.
Unknown: YY is not well characterized for
disease X;
Question: thus, in this current study, we have
characterized YY in 203 patients
with acute cases of disease X.
Approach: To do this, we have measured YY
by Z methods.
Known
Unknown
Q
A
Introduction outline
Hypothesis paper
“The immune response to dengue virus infection
is poorly defined. Previously published animal
models of dengue virus infection have not
characterized the immunological responses
very extensively (Author, 2005). To
characterize the primary immune response in
mice infected with dengue virus serotype 2
strain, we employed two complementary
approaches: first we measured…”
Known
Unknown
Q
A
Known:
Methods Paper
Model # 2
The current approach is YY (REF).
Unknown: YY is limited because of A, B, and C.
Method:
Thus, we have developed ZZ, which
has the following advantages: D, E, and F.
Approach: To do this, we altered YY by doing X.
Known
Unknown
Q
A
Introduction Summary
Methods paper
“The existing strain-typing methods based on
dengue viral genetic differences are
constrained by technical requirements or cost
considerations and cannot be easily applied
to investigate a dengue epidemic where it is
occurring. In this report, we characterized a
novel method, one-step PCR, and evaluate
its use as a simple and rapid alternative for
strain typing in endemic settings.”
Last paragraph
•
Most important paragraph of the introduction
•
Many readers will only read this paragraph of your
introduction
•
Include your main finding
(in most journals ---but not always)
•
Content similar to:
 Abstract
 Parts of discussion
Introductions should:
- motivate the reader!
- summarize literature.
- be as brief as possible.
- go from general to specific.