Have you ever struggled to write your introduction? If your answer to this question is a desperate “Yes”, don’t worry, you are not alone. The introduction is usually the hardest part of an article to write, especially if you don’t know how to structure it. Luckily, introductions of scientific articles are structured according to a defined template. In this post, I describe this template and give examples for you to see how it is concretely implemented (see here to get an overview of the structure of the whole article and here to download the template of your introduction).

The introduction of a scientific article follows an inverted triangle shape. It starts broadly with the general research topic and progressively narrows down to your research question and the study that you performed to answer this question. You can divide your introduction into five successive levels that become more and more specific. Here are these different levels.

Level 1. Start by introducing your research topic

The first paragraph(s) of the introduction aim(s) to introduce your research topic. Your research topic is the main character in your story. Just as a good story requires a compelling hero, a good scientific paper relies on an interesting research topic. Therefore, your first introductory paragraph(s) must convince your readers of the importance of your topic. Let’s take an example!

Imagine that you have run a study to test the efficacy of a new treatment to cure a disease called Dragon Pox – Dragon Pox is an imaginary disease that affects wizards and witches, like chickenpox (see the Harry Potter series). When writing the paper describing your research on this disease, you could start your introduction by emphasizing the preponderance of Dragon Pox.

“Dragon pox is one of the most problematic infectious diseases today. It is the most common disease in children under 12 years of age and about 2 out of 5 people contract it in their lifetime. Dragon pox causes green and purple rashes and sparks that come out of the nostrils when the patient sneezes. These symptoms can escalate, leading to serious complications (pneumonia, encephalitis, etc.) and significant sequelae (respiratory failure, mottled skin). In addition, in 8.4% of cases, the infection results in the patient’s death. In 2021, the fatal consequences and high prevalence of dragon pox have prompted the Wizzard Health Organization (WHO) to declare it as the priority public health issue of the next decade.”

After having read these few sentences, your reader knows that

1. the article is about Dragon Pox,
2. that it’s an important topic.

Your introduction should begin as broadly as possible to appeal to a wide audience. That being said, the breadth of your introduction should also depend on your readership. If your paper is aimed at specialists, being too general may bore them and make them lose interest in your research. So, when writing the first paragraph(s) of your introduction, it is important to keep in mind who your audience is and what they care about.

Level 2. Delineate your research niche

Once you have established your research topic and emphasized its importance, the next step is to narrow your paper down to your research niche. Your niche defines the specialized area you are researching; it is a more focused domain than the general research topic. For example, in the case of dragon pox, your niche could be one of the following topics:
            – its diagnosis,
            – its treatment,
            – its mechanism of contagion,
            – the increased vulnerability of some people to this disease,
            – the genetic code of the virus,
            – the proteins that make up the virus’ membrane,
            – its evolutionary origins…

At Level 2, you need to provide general background information about what has been done so far in this niche. For instance, if your research is about dragon pox treatment, you could explain which drugs already exist to cure the disease.

“Dragon pox is primarily treated with anti-herpetic agents. Indeed, the disease results from a primary infection caused by the varicella-monster virus (VMV), which belongs to the human herpesvirus family. Recent studies suggest that oral aclocyvir is the most efficient method against VMV. Aclocyvir is a nucleoside analog that mimics guasonine…“

Level 3. Describe the problem that you will address

Once you have defined your niche, you need to describe the problem that your research will address. A good story needs a compelling character facing a daunting challenge. Which challenge does your article tackle? Why is this challenge important to your readers? These are the two questions that you need to answer at Level 3.

Let’s go back to our example. If you have tested a new treatment for Dragon Pox, it’s likely because the usual treatment poses some problems that your new treatment aims at circumventing. So your next paragraphs might be something like:

“Research shows that treatment by oral aclocyvir reduces by 23% the risks of complications following VMV infection. Unfortunately, aclocyvir has many side effects, such as nausea, appetite loss, or diarrhea. These side-effects cause one-third of the patients to interrupt the treatment before completion and thus considerably reduce its efficiency.“

At Level 3, it is essential that you frame your research question as a problem. Indeed, humans have a propensity to pay attention to negative information. In psychology, this phenomenon is called negativity bias. By highlighting the problems and risks associated with the current state of knowledge, you create tension in your readers. This tension motivates them to continue reading your article and makes them want you to find a solution to the problem.

Level 4. Provide a solution

At Level 3, you have created tension in your readers by highlighting a serious problem in your niche; at Level 4, you begin to resolve that tension by explaining how you will fix that problem.

In scientific writing, it’s important to convince your reader that the solution you’re proposing to solve this problem has a rational basis. You can do that in two ways:
1) by explaining the logic that led you to consider the solution tested in your paper,
2) and by providing arguments and citing already existing evidence to support your hypotheses and/or theory.

For instance:

“Recent research suggests that the side effects of oral aclocyvir may be counteracted by adeninoside. Adeninoside appears to decrease nausea and loss of appetite. In recent years, physicians have begun to use a combination of oral acyclovir and adenoside to treat severe forms of herpes. Early clinical trials indicate fewer side effects and better patient acceptance of the treatment. Thus, this approach appears to be successful in the treatment of herpes. However, it has never been tested in patients with VMV. The present study intends to fill this gap.”

As you can see in this example, here again, I emphasize the gap that the research intends to fill. And, I’m sure you’ve guessed it, here again, I’m creating tension in the reader.

Level 5. State your hypotheses and introduce your methods

We are now at the end of the introduction. You have already set the stage for your study; now it is time to state your hypotheses (if you have any) and/or introduce the methods that you chose to test them. For example:

“In the study reported in this article, we investigated the efficacy of a new treatment to cure Dragon Pox. We tested the hypothesis that the administration of adeninoside reduces the side-effects of aclocyvir and, thus, increases the treatment efficiency. To that aim, we compared two groups of patients treated with either aclocyvir alone or aclocyvir combined with adeninoside…”

Introducing your methods serves two purposes. First, it facilitates the transition to the materials and methods section by giving your readers an overview of your research. This should help them better understand the study you have conducted. Second, it allows you to explain the reasons for the methodological approach you decided to take. This is especially important if you are relying on a new approach or if you are writing for an audience that is unfamiliar with this type of methodology. You can use the last paragraphs of the introduction to present the rationale for your methods and their value in solving the problem your paper addresses.

Be convincing, not exhaustive

If you are writing a scientific article, you certainly know a lot about this topic. That’s a good thing! It’s necessary to do good research. But one thing is important to keep in mind: You don’t need to demonstrate all your knowledge in your article.

A scientific article is not an essay that your teacher will grade. It has a different purpose. Indeed, the goal of an essay is to convince your teacher that you have the knowledge and skills he or she expects from you. These expectations vary from teacher to teacher, but some teachers might enjoy seeing that you know a lot about the topic at hand. The goal of a scientific article is to captivate the attention of your readers and convince them of the soundness of your research.

Your readers don’t care about you. They want to read something interesting that they can trust. Your job is to take their hands and smoothly lead them to your research question, your hypotheses, and, eventually, your methods. Everything that you write in the introduction should contribute to this progression. If a piece of information is not directly useful to understand the necessity of your study, it doesn’t belong to your introduction. Go right to the point and avoid complex detours. When it comes to being convincing, less is usually more.

In Sum

In this post, we’ve seen that the introduction to a scientific article contains five main levels that describe: 1) your general research topic, 2) the more specific niche, 3) the problem that your research will address, 4) the solution that you intend to bring to this problem, and 5) an overview of your hypotheses and methods. Follow these five steps and you’ll write an introduction that will captivate your readers. It’s that easy!

To make it easier for you, I’ve created a template to write your introduction, with instructions almost as simple to follow as a cooking recipe. You can find this template below. To learn more about the structure of scientific papers, read my Ultimate Guide to Scientific Writing, as well as my posts on the Materials and Methods, Results, and Discussion sections. Good luck with your paper!

Gaya