The introduction is the section most often rewritten and the one that looks most alike from one paper to the next. Nearly all begin with how important the topic is, go on to a review of the literature and end with “the aim of this study was…”. It is a correct structure and yet it often fails to convince, because each paragraph is true but none leads to the next.
A good introduction is a funnel with a direction: it starts from a field, narrows to a specific problem and ends at the question your study answers, so that the reader arrives at the aim thinking “of course, that is what was missing”. The editor decides in those first pages whether to read you with interest or in a hurry.
This guide gives you a four-move structure, a rough length, an example and the mistakes manuscripts repeat most. It works for a journal article and, with adjustments, for a thesis introduction.
The introduction has a single job: to justify your study. It is not the place to summarise everything known about the topic or to show how much you have read. It is the place where someone who has not followed your research understands which field you are talking about, what is known, what is not yet known and why your study is the reasonable way to find out.
That explains the length. In a journal article the introduction usually takes between one page and a page and a half, and less if the journal sets a strict word limit. In a thesis it can be a whole chapter, but it is still an argument, not a catalogue. If a sentence does not help justify the study, it goes, however interesting it is.
Think of the introduction as four linked moves. Each can be one paragraph or several, but the order matters because each move prepares the next.
Start with the construct or the problem, not with humanity. Define the central concept with a solid reference and place the topic in its field with one or two facts that explain why it matters: prevalence, cost, impact. One or two sentences are enough. Avoid openings such as “Since the dawn of time…” or “In today’s society…”, which inform nobody and delay the reader’s entry into your topic.
Here goes the literature review, but with a principle: it is organised by ideas, not by authors. Instead of “Smith (2019) found…, Jones (2020) found…”, write what the literature allows you to claim and cite those who support it. Each paragraph defends one idea and backs it with studies. If results conflict, this is the moment to say so, because that is often where the question is born.
This is the sentence that changes the tone of the whole introduction: what is known reaches this far, but something is left unresolved. It often starts with “However…” or “Despite this…”, and points to a specific gap: a population not studied, a relationship untested, a conflicting result, a methodological limitation of earlier studies.
It is the most important move and the one that fails most. A gap is not “there are few studies in my country” or “I have found nothing like this”. It is an unanswered question that a reader would care to see answered. If you cannot state it clearly, the study is not yet justified.
Close with what you do to fill the gap: the aim, the hypotheses if there are any and, in a sentence, the design. It should read as the natural consequence of the pivot: if the gap was “the X–Y relationship has not been tested in adolescents”, the aim is to test it in adolescents. If you put here an aim that does not answer the previous gap, the reader notices. There is more on wording them in the guide to objectives and hypotheses.
Move 1: “Test anxiety affects a considerable share of university students and is associated with poorer performance and higher dropout (Author, year).”
Move 2: “Cognitive restructuring programmes reduce anxiety in this setting (Author, year; Author, year), and relaxation programmes do so with smaller effects (Author, year).”
Move 3: “However, almost all studies have used health-science samples, and it is unknown whether effects hold in degrees with oral examinations, where social exposure differs.”
Move 4: “This study tests whether a brief cognitive restructuring programme reduces anxiety about oral examinations in humanities students, compared with a waitlist.”
Each sentence prepares the next, and the aim at the end is the direct answer to the gap in move 3. In a real paper each move takes one or several paragraphs with its references, but the logic is the same.
A reviewer recognises them on the first page:
Many authors write the introduction first and never touch it again. It is the opposite of what helps. Once you know what you found, you can adjust the funnel so it leads to exactly that: prioritise the literature you will use in the discussion and cut what you will not. That does not mean bending the introduction so the results look expected (it is called HARKing, and a reviewer detects it); it means writing it with the knowledge of what the reader needs to understand your study.
To check it works, try the isolated-reading test: ask someone outside the topic to read only the introduction and tell you, in their own words, what problem you solve and why. If they cannot, the funnel has a broken stretch.
If you are writing your introduction now, paste it below and you will see the first objection a reviewer would raise, with the exact sentence from your text where it applies and what it would take to fix it. It looks at what this guide covers: whether the gap in the literature is real or merely asserted, whether the hypotheses follow from what you have just laid out, whether the citations support what you use them for, and whether the last paragraph announces aims the design then addresses.
It returns one objection, the one that weighs most, so you know where to start. It needs at least 350 characters, the introduction does not need to be finished, and what you paste is not stored. If deciding something would require seeing the method or the results, it says so separately instead of turning it into an objection.
Between one page and a page and a half in most journals, and less if the word limit is strict. Check the journal’s author instructions: some ask for very short introductions and others allow more development.
The aim of the study, the hypotheses if there are any and, in a sentence, the design. It should be the natural consequence of the gap you set out just before. Do not put results or conclusions here.
As a specific unanswered question that a reader would care to see answered: a population not studied, a relationship untested, conflicting results or a limitation of earlier studies. “There are few studies” is not a gap; you have to explain why it matters that they are missing.
The logic is the same, but a thesis is longer and has more room for the theoretical framework. It is still an argument that leads to your study. Many theses separate the theoretical framework from the introduction, which then stays shorter.
Yes, it is the commonest signal and it works, because the reader recognises the change of tone. What matters is not the word but what follows: a specific, justified gap.
Cite it when it is relevant to the argument, not to add citations. A reviewer distrusts self-citations that add nothing, and also those that are excessive relative to the total bibliography.