1 What is the Importance of an Introduction?

An Introduction to a scientific paper familiarizes the reader with the background of the issue at hand. It must reflect why the issue is topical and its current importance in the vast sea of research being done globally. It lays the foundation of biomedical writing and is the first portion of an article according to the IMRAD pattern (Introduction, Methodology, Results, and Discussion) [1].

It provides the flavour of the article and many authors have used phrases to describe it for example—'like a gate of the city’ [2], ‘the beginning is half of the whole’ [3], ‘an introduction is not just wrestling with words to fit the facts, but it also strongly modulated by perception of the anticipated reactions of peer colleagues’, [4] and ‘an introduction is like the trailer to a movie’. A good introduction helps captivate the reader early.

figure a

2 What Are the Principles of Writing a Good Introduction?

A good introduction will ‘sell’ an article to a journal editor, reviewer, and finally to a reader [3]. It should contain the following information [5, 6]:

  • The known—The background scientific data

  • The unknown—Gaps in the current knowledge

  • Research hypothesis or question

  • Methodologies used for the study

The known consist of citations from a review of the literature whereas the unknown is the new work to be undertaken. This part should address how your work is the required missing piece of the puzzle.

3 What Are the Models of Writing an Introduction?

These are:

  1. 1.

    The Problem-solving model

First described by Swales et al. in 1979, in this model the writer should identify the ‘problem’ in the research, address the ‘solution’ and also write about ‘the criteria for evaluating the problem’ [7, 8].

  1. 2.

    The CARS model that stands for Creating A Research Space [9, 10].

The two important components of this model are:

  • Establishing a territory (situation)

  • Establishing a niche (problem)

  • Occupying a niche (the solution)

In this popular model, one can add a fourth point, i.e., a conclusion [10].

4 What Is Establishing a Territory?

This includes: [9]

  • Stating the general topic and providing some background about it.

  • Providing a brief and relevant review of the literature related to the topic.

  • Adding a paragraph on the scope of the topic including the need for your study.

5 What Is Establishing a Niche?

Establishing a niche includes:

  • Stating the importance of the problem.

  • Outlining the current situation regarding the problem citing both global and national data.

  • Evaluating the current situation (advantages/ disadvantages).

  • Identifying the gaps.

  • Emphasizing the importance of the proposed research and how the gaps will be addressed.

  • Stating the research problem/ questions.

  • Stating the hypotheses briefly.

Figure 17.1 depicts how the introduction needs to be written. A scientific paper should have an introduction in the form of an inverted pyramid. The writer should start with the general information about the topic and subsequently narrow it down to the specific topic-related introduction.

Fig. 17.1
figure 1

Flow of ideas from the general to the specific

6 What Does Occupying a Niche Mean?

This is the third portion of the introduction and defines the rationale of the research and states the research question. If this is missing the reviewers will not understand the logic for publication and is a common reason for rejection [11, 12]. An example of this is given below:

Till date, no study has been done to see the effectiveness of a mesh alone or the effectiveness of double suturing along with a mesh in the closure of an umbilical hernia regarding the incidence of failure. So, the present study is aimed at comparing the effectiveness of a mesh alone versus the double suturing technique along with a mesh.

7 How Long Should the Introduction Be?

For a project protocol, the introduction should be about 1–2 pages long and for a thesis it should be 3–5 pages in a double-spaced typed setting. For a scientific paper it should be less than 10–15% of the total length of the manuscript [13, 14].

8 How Many References Should an Introduction Have?

All sections in a scientific manuscript except the conclusion should contain references. It has been suggested that an introduction should have four or five or at the most one-third of the references in the whole paper [15].

9 What Are the Important Points Which Should be not Missed in an Introduction?

An introduction paves the way forward for the subsequent sections of the article. Frequently well-planned studies are rejected by journals during review because of the simple reason that the authors failed to clarify the data in this section to justify the study [16, 17]. Thus, the existing gap in knowledge should be clearly brought out in this section (Fig. 17.2).

Fig. 17.2
figure 2

How should the abstract, introduction, and discussion look

The following points are important to consider:

  • The introduction should be written in simple sentences and in the present tense.

  • Many of the terms will be introduced in this section for the first time and these will require abbreviations to be used later.

  • The references in this section should be to papers published in quality journals (e.g., having a high impact factor).

  • The aims, problems, and hypotheses should be clearly mentioned.

  • Start with a generalization on the topic and go on to specific information relevant to your research.

10 Example of an Introduction

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11 Conclusions

  • An Introduction is a brief account of what the study is about. It should be short, crisp, and complete.

  • It has to move from a general to a specific research topic and must include the need for the present study.

  • The Introduction should include data from a literature search, i.e., what is already known about this subject and progress to what we hope to add to this knowledge.