The introduction is the first thing your marker reads and the section that shapes their entire experience of your essay. Most undergraduate introductions are weaker than they need to be — not because students don't understand the material, but because they've been taught to summarise rather than argue. Here's what needs to change.
The most common mistake: the topic tour
A topic tour introduction goes through the subjects the essay will cover, in order, without making any argumentative move. 'This essay will first examine X, then consider Y, before concluding with Z.' This tells a marker nothing about your thinking. It reads as a contents page, not an argument. Most UK marking criteria at Level 5 and above explicitly reward 'clear and sustained argument' — and a topic tour signals the opposite from the first paragraph.
What a strong introduction actually does
A strong introduction does three things in order. First, it establishes the context or problem — why does this question matter? What is genuinely at stake? Second, it states your thesis — your answer to the question, in one or two clear sentences. Third, it signals your method — how you will demonstrate your argument, briefly. This is not a contents list. It is a roadmap that shows you know where you're going and why.
The thesis statement: the most important sentence in your essay
Your thesis statement is a direct, arguable claim — not a description of a topic, not a question, and not a statement of fact. Compare these two: Weak: 'Corporate social responsibility is an important issue in modern business.' This is undeniable and therefore uninteresting. Strong: 'Despite widespread adoption of CSR frameworks, the empirical evidence for their positive impact on long-term firm value remains inconclusive — suggesting that CSR functions primarily as reputational risk management rather than genuine stakeholder value creation.' This is arguable. A marker reading this knows exactly what the essay will try to prove.
The 20-minute fix
Open your current introduction. Highlight every sentence that describes what you will do ('this essay will...' or 'firstly, this essay examines...'). Delete them. Now write one sentence that answers the essay question directly. That is your thesis. Write one sentence that says why this answer is not obvious — what is the tension, contradiction, or complexity that makes this worth arguing? That is your context. Write one sentence that says how you will demonstrate your thesis — not a list of topics, but a method. Now you have a three-sentence introduction that does more work than most 200-word ones.
What to do with the rest of the introduction
Once you have your three core sentences, you can expand around them — providing the minimum necessary context for a reader unfamiliar with the debate, defining any key terms your argument depends on, and acknowledging a counterposition you will address. The introduction should be approximately 10% of your essay's word count. For a 2,000-word essay, that's 200 words. For a 3,000-word essay, 300 words. If yours is longer than that, it probably contains material that belongs in the body.