Lecture Outline

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Lecture Outline
How to write the introduction

• Function of Introduction
• Length
• 3. Parts
• 4. Examples

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Introduction Function
Motivate the reader!
Introduction
Methods
Results
In hopes they will read the entire paper THROUGH
the discussion
Discussion
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Function
Intro

• 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
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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

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Length

• Keep it BRIEF
• See your target journal for average length of
  introduction
• Try to limit the introduction to 3 or 5
  paragraphs

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Introduction
Methods
Lets dissect the introduction into parts.
Results
Discussion
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Flow of Introduction
Ref M. Zeiger
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Flow of Introduction
Known
Unknown
Question
Approach
Structure your paragraphs
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First paragraph

• Very broad and general
• 2. Orients reader to importance of topic

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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.

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Relationship to other studies

• 1. Summarize previous knowledge
• 2. Prepare the scene for your work
• Reveal gaps and holes
• Raise a question

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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.

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State your question

• What specific hypothesis are you testing?
• What exact process are you describing?
• What method are you trying to improve?

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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.

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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.

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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

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Methods PaperModel 2
Known
Unknown
Q
A
Known 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.
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Known
Introduction Summary Methods paper
Unknown
Q
A

• 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.

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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

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Introductions should

• - motivate the reader!
• - summarize literature.
• - be as brief as possible.
• - go from general to specific.