How do I write a thesis introduction?

The introduction is the chapter examiners read most carefully and the one most often written first, when you knew least. Both facts point the same way: draft it early as a planning document and rewrite it completely at the end.

The four moves have a fixed order because each one depends on the last. Significance first, because a reader who does not see why the topic matters will not care what is missing from it. Then the gap, stated specifically enough to be checkable. Then your question and your contribution, which is what fills the gap. Then the map of the thesis.

The move most often done badly is significance. Opening with a broad statement about the importance of the general area is the weakest available start, because it is true of everything and specific to nothing. A better opening names a concrete problem or a real disagreement in the field, in the first two sentences.

The contribution statement is the second. Many introductions describe what the thesis does without ever saying what it adds. "This thesis examines X in Y" is an activity. "This thesis shows that X does not hold in Y, and explains why" is a contribution, and it is what an examiner will test.

Naming the problem also means naming who has it. Zhang's rules for research papers ask you to keep the text self-contained, supply the background an intended reader actually needs, and define uncommon terms instead of assuming your reader shares your training (Zhang, 2014, p. 2). Pautasso opens the review guidance with the same instruction, define the topic and define the audience before writing anything (Pautasso, 2013, p. 1). For a thesis introduction that rules out both failure modes, an opening built from specialist vocabulary no examiner outside your subfield can parse, and an opening that teaches the whole field from scratch.

Stating the gap specifically enough to be checkable means saying what kind of gap it is. Lingard names four: a straightforward knowledge deficit, a methodological or philosophical shortcoming, an active controversy, and a widely held assumption nobody has tested (Lingard, 2018, Part I, pp. 48-49). Her examples run from the absence of research on longitudinal integrated clerkships and student abuse, to surveys that count medical errors without asking residents about their own experience of them, to disagreement over what professionalism in medicine means, to the untested belief that technology will fix teamwork problems. "Few studies have examined" commits to none of these. Naming the type does, and it also forces coherence between the gap and the method you chose to address it (Lingard, 2018, Part I, p. 49).

What does an introduction have to establish?

That the topic matters to someone beyond you, that a specific gap exists, that your question addresses it, and that the thesis is organized in a way the reader can follow. An examiner who finishes the introduction should be able to state your contribution in one sentence.

Test this directly. Give the introduction to someone outside your subfield and ask them to write down, in one sentence, what the thesis contributes. If they cannot, or if they write something you disagree with, the introduction has not done its job yet.

The chapter map at the end deserves more care than it usually gets. One short paragraph per chapter, saying what each does rather than what it is about, gives the examiner a structure to read against.

How much literature belongs in the introduction?

Only what is needed to establish the gap, usually a page or two of the most important work. The introduction shows the reader that a question exists. The review chapter shows them the field in detail. Repeating the review in miniature makes both chapters weaker.

The test is whether a citation in the introduction is doing argumentative work. If it establishes that the problem is real, or that a specific piece is missing, it belongs. If it is there for completeness, it belongs in the review.

Lingard's name for the alternative is the laundry list, the review that reproduces everything the author has read (Lingard, 2018, Part I, pp. 47-48). The replacement is a map: draw the established areas of knowledge, but arrange them around the white space your thesis will occupy, and stop short of filling the map so completely that nothing is left to do (Lingard, 2018, Part I, p. 47). Pautasso emphasizes something different, critical coverage, so that a reader finishes the review knowing the field's major achievements, its areas of debate, and its outstanding questions (Pautasso, 2013, p. 3). In the introduction, apply Lingard's selectivity. Pautasso's coverage test is what the review chapter has to pass.

Where the boundary is genuinely awkward, decide by what the reader needs at that moment. In the introduction they need to accept that a question is worth asking. Anything more is a delay before the thing they came for, which is your question.

Check the gap again before you submit. Pautasso warns that a claimed gap can stop being a gap while you write, through papers in press, studies indexed only recently, or older work that went uncited for years and was then rediscovered, and recommends searching the literature once more during revision (Pautasso, 2013, pp. 3-4). The preparation matters as much as the check. Record your search terms so the search can be repeated, set exclusion criteria early, use a reference manager, and read previous reviews alongside primary studies (Pautasso, 2013, p. 1). A thesis introduction is selective in what it presents and systematic in what stands behind it.