How to Start an Introduction? Examples from 98,093 Research Papers

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The examples below are from 98,093 full-text PubMed research papers that I analyzed in order to explore common ways to start the Introduction section.

The research papers included in this analysis were selected at random from those uploaded to PubMed Central between the years 2016 and 2021. Note that I used the BioC API to download the data (see the References section below).

Examples of how to start an Introduction section

The Introduction should start by describing the general context of your work. Your aim should be to convince the reader that the topic of your research is interesting. [For more information, see: How to Write & Publish a Research Paper: Step-by-Step Guide]

The Introduction can:

1. Start with a definition

Here, you define or provide an overview of the problem you are about to study.

For example, here’s the beginning of the Introduction section of a study on the mental health status of students:

“The World Health Organization defines mental health as a state of well-being in which an individual realizes his or her own abilities, can cope with the normal stresses of life, can work productively and is able to make a contribution to his or her community.”

Source: Taken from the Introduction of this PubMed article

2. Start by reviewing the results of other studies

Here, you review what is already known about the subject. For example, you can cite some data about the severity of the problem you are about to study.

Here’s the beginning of the Introduction section of a study on the treatment of testicular cancer:

“According to a publication by the American Cancer Society, there was an estimated 8590 new cases of testicular cancer in the United States in 2012, accounting for only 360 deaths.”

Source: Taken from the Introduction of this PubMed article

2. Start with a question

In general, the question at the start of the Introduction section should draw the reader’s attention, provide a preview of the aim of your study, and express the significance of your work.

Note however, that it is somewhat uncommon for an introduction to start with a question: in our sample of 98.093 research papers, only 247 (0.25%) papers started their Introduction with a question.

For example, here’s the beginning of the Introduction section of a study whose aim is to explain the way the brain perceives the world:

“How does the brain interpret information from the senses? This unresolved question carries fundamental importance for neuroscience.”

Source: Taken from the Introduction of this PubMed article

Common words used to start an introduction

  • “It is well known that…”
  • “This is the first study…”
  • “In recent years…”
  • “Over the past…”
  • “In the last…”
  • “According to…”

References

  • Comeau DC, Wei CH, Islamaj Doğan R, and Lu Z. PMC text mining subset in BioC: about 3 million full text articles and growing, Bioinformatics, btz070, 2019.

Further reading