Criteria for Success
A successful introduction has:
- General Background. Your research is anchored in a general topic that everyone in your audience cares about.
- Specific Background. All information connects your project with the general topic that everyone cares about. The information accurately represents the field and is correctly referenced.
- Statement of Problem or Knowledge Gap. The question you address is clearly articulated, connected to the background, and appears meaningful.
- Here we show… Your findings and their implications fill the demonstrated gap.
This structure is like the first half of an Abstract.
Identify Your Purpose
Your paper’s Introduction should provide your readers with the information they need to grasp, appreciate, and build on the knowledge you present. The Introduction should:
- demarcate the overall scientific settings of your research (in the “General Background”).
- impart the minimum essential information about the key actors: e.g., chemical reactions, signaling pathways, techniques, mathematical models (in the “Specific Background”).
- give evidence of the incompleteness of the current understanding and of the value of investigating the field further (in the “Knowledge Gap”).
- give a brief preview of your findings and how they relate to the central question (in the “Here we show”).
Having read the Introduction, the reader should feel well-equipped and eager to understand your study and its significance.
Analyze Your Audience
Scientists in your specific field will probably understand your work’s motivation whether they read your Introduction or not. They might even skip the Introduction and focus on the Methods and Results. Outsiders are the people who will benefit most from a well-crafted Introduction. This means:
- scientists outside your research area,
- clinical care, public health, policy, education, or consulting professionals who might benefit from your work, and
- editors assessing whether your work might be a good fit for their journal.
Focusing on outside readers will chiefly affect two parts of the Introduction:
- It will increase the General Background’s breadth. Imagine you are studying a molecule that modulates the effect that influenza has on DNA damage repair. For an insider audience, you might write a paper that begins with a summary of known protein complexes taking part in the repair of DNA double-stranded breaks. For an outsider audience at a broad-readership journal, the General Background—the thing everybody cares about—will broaden from protein complexes to the flu and DNA damage in general. You might instead start off with information about the rate and morbidity of the flu virus and the different categories of DNA damage.
- It will lead to a less technical Knowledge Gap. The more basic the question posed in the Knowledge Gap, the more people will care about it. Take the time to identify the simplest, most fundamental question your work answers. More technical questions will attract smaller, more specialized readership. If you make your results seem less general than they actually are, you immediately lose readership.
Breadth, length, and comprehensiveness of the Introduction are highly dependent on the journal you submit to. Analyze papers from your target journal and follow the journal’s guidelines.
Orient outside readers
Start off with something everybody cares about. Then give your reader a sense of past accomplishments, current contradictions, and competing theories in the field. Cite previous work that illustrates your narrative and gives a balanced description of the landscape of research groups in the field. Give credit to others for their contribution to your scientific topic.
Give your readers the technical details they need (and nothing more)
After having brought to your audience’s attention the overall value of your study, you must give them all the tools needed to understand the details of your approach and of your results. Familiarize the reader with all molecules pertinent to your work, or with the modeling methodology you will draw on, or with prior technologies commonly used to probe specimens similar to yours.
Point out how your methods stand out when contrasted to previous approaches, and how they are apt to tackle the question left unanswered by previous work.
Declare all key terms and all acronyms. They should be the main characters in your paper from the outset.
Remove anything that is not related to the Results or Discussion. By including unnecessary knowledge, you run the risk of overpromising, making a reader expect to hear more about a topic and then leaving them hanging. Your purpose is not to showcase the breadth of your knowledge, but instead to give readers all the tools they need to understand your results and their significance.
Define a narrative
You’ll probably want to write your Introduction after you write the Results and Discussion sections. The story you choose for the Results and Discussion sections will determine which theories and past research or methodologies need to be presented in the Introduction.
Connect the “Here we show” part of your Introduction with the Results and Discussion rather than Methods. Figure out what you can unambiguously claim about your data (Results) and what you might conjecture (Discussion), and foreshadow those things in the “Here we show.”
Use appropriate style
Keep in mind that the sections described here may not be appropriate for the data/results you are planning to present. Make sure that you choose the divisions in your paper to match what you are writing, and don’t confine yourself to Introduction/Methods/Results/Conclusions if it doesn’t make sense for your paper.