A thesis statement is your answer to the essay question, put in a sentence or two near the start, so the reader knows what the essay sets out to prove. Learning how to write a thesis statement is mostly learning what to leave out: the undisputed fact, the announced topic, the list. EdCitation publishes this guide; its examples are ours, and labelled so.
We read every rule on 26 September 2026, at ten universities' writing centres and libraries: Harvard, the University of North Carolina at Chapel Hill (UNC), Purdue, Indiana and the University of Maryland Global Campus (UMGC) in the US; Southampton, Hull, London South Bank (LSBU) and Sheffield in the UK; Toronto in Canada. They differ on length, place and, in the UK, the name.
EdCitation never writes a thesis statement, or any part of an essay. It does the checking around one: Check your paper reads the brief the thesis must answer, Find sources shows whether evidence exists for the claim, and Cite a source builds each reference from the publisher's record.
What is a thesis statement in an essay?
A thesis statement is the sentence, or short passage, in an essay's introduction that states the essay's central claim: the answer it will defend. Harvard College Writing Center (n.d.) places that claim early, followed by the argument that supports it. Indiana University Bloomington Writing Tutorial Services (n.d.) calls it the argument condensed into one or two sentences. This is the essay sense; a dissertation's thesis is a whole document.
Do UK essays use the term?
Some UK universities do and some do not. University of Hull Library (2026) says the term comes from American guides and is not UK usage, but the introduction must still state the overarching argument, its "mega-argument". Southampton and LSBU teach the thesis statement by name, and University of Sheffield (n.d.) speaks of a claim that usually sits inside it.
What makes a thesis statement strong?
A strong thesis statement makes a claim a reader could dispute, is specific enough to prove in the space, answers the question set, and shows the shape of the argument.
Arguable and specific
Harvard's test is whether a thoughtful reader could disagree, and it names both failures of scope: too narrow leaves nothing to say, too broad cannot be supported. University of North Carolina at Chapel Hill Writing Center (n.d.-b) says stating facts is summarising, not arguing, and suggests replacing words like "good" with the reasons why. University of Southampton Library (2026) shows three drafts narrowing a "negative impact" on prisoners to a named harm, their mental health.
Answers the question and sets up the structure
UNC's first question is whether the thesis answers the question; UMGC wants it to mirror the prompt. The fuller test is in does my paper answer the assignment question. Indiana notes that strong theses often turn on words such as because, although and however, which show how the parts connect. How paragraphs then hang from it is in how to structure an essay.
What kinds of thesis statement are there?
The kind of thesis follows the kind of essay. Purdue Online Writing Lab (n.d.) names three, below with our own examples; a compare and contrast thesis has its own shape, shown in the literature example further down.
| Kind | What it does | Our example |
|---|---|---|
| Argumentative | Takes a side on policy or value | Schools should keep phones out of lessons, but the evidence does not yet justify a whole-day ban. |
| Analytical | Breaks a text or problem into parts and says what they show | The witches in Macbeth never tell Macbeth to kill, so the play leaves open whether the prophecy causes the murder or only licenses it. |
| Expository | Explains without taking a side | Photosynthesis runs in two stages: light-dependent reactions that capture energy, and the Calvin cycle, which uses it to turn carbon dioxide into sugar. |
Must every thesis be arguable?
No, and here the guides part company. Purdue's expository example describes without taking a side, while Harvard and UNC treat a descriptive thesis as weak. If the brief says explain, an explanatory thesis fits; if it says evaluate or argue, description is a fault. Southampton offers an aim statement for work without a central argument, and Toronto says exploratory essays may not want a thesis at all. For comparisons, University of North Carolina at Chapel Hill Writing Center (n.d.-a) rejects a thesis that only says two things are alike in some ways and different in others, and asks why the difference matters.
Where does the thesis statement go, and how long should it be?
In most essays the thesis statement goes at the end of the introduction, in one sentence. Some guides allow two or three sentences, and one sets no fixed place.
| Guide | Where it goes | Thesis statement length |
|---|---|---|
| UNC (US) | Most often the end of the first paragraph | Usually one sentence |
| Purdue (US) | Usually the end of the first paragraph | No figure |
| Indiana (US) | Early | One or two sentences |
| Southampton (UK) | The introduction | Usually one; a few in longer work |
| Hull (UK) | The introduction, with a map | No figure; its sample claims in one sentence and maps in the next |
| Toronto (Canada) | Usually the first paragraph; no rigid rule | Two or three if needed, or a paragraph |
When may it be more than one sentence?
When one sentence cannot hold the claim clearly. Procter (n.d.), writing for Toronto, calls the one-sentence rule a myth; a stronger Toronto example uses one sentence to set two explanations aside and a second to say what the data show. In a short essay, aim for one.
Is "This essay will argue that" allowed?
The guides differ. UMGC lists announcements such as "this paper will discuss" among things to avoid, yet Southampton's final draft opens "This essay argues that", LSBU's example "This essay will argue that", and Hull's sample "This essay will claim that". The fault is an announcement with no claim: "This essay will discuss phone bans" names a topic, while "This essay argues that phone bans..." frames an answer. Follow your department.
How do you write a working thesis that changes as you research?
Write a first answer early, test it against the evidence, and rewrite it until it claims only what the essay can prove. UNC says changing a working thesis is fine, and Southampton treats it as a hypothesis until the essay is nearly done.
- Turn the brief into one question. Check your paper turns the brief into a free checklist and lists its task sentences apart.
- Write a rough one-sentence answer: your working thesis.
- Search for evidence for the claim itself. Find sources searches about 300 million published works, by topic or by the claim a sentence needs to support.
- Narrow the thesis to what the evidence can carry.
- Break it into the claims each paragraph will prove.
- Draft, then compare thesis and body. Southampton's rule: if your thinking moved, rewrite the thesis; if the body wandered, cut the body.
- Build references with Cite a source and check them with Verify references.
What faults do markers find in thesis statements?
Five recur across the guides. The weak examples are ours.
| Fault | Our weak example | Named by | The fix |
|---|---|---|---|
| A statement of fact | "Many countries have introduced rules on phones in schools." | UNC, Indiana, UMGC | Say what the fact means for the question |
| An announcement | "This essay will discuss phone bans in schools." | UMGC, Indiana | Give the answer, not the topic |
| Too broad | "Technology has changed education." | Harvard, Indiana, Toronto | Narrow to one claim the word limit can carry |
| A list | "The League failed because of the USA, the Depression, Manchuria and Abyssinia." | Indiana, Toronto, MIT | Say how the points relate and which matters most |
| Another question's answer | "Phones are distracting", for a question about whole-day bans | UNC, UMGC | Return to the task word |
Indiana asks for one main idea; Toronto says supporting points need not come in any set number; an MIT handout prefers two ideas developed to five mentioned (Kaiser & Jones, 2010b).
Thesis statement examples: weak and strong, in three subjects
These questions and theses are ours. The strong versions show a thesis's form; they are not verdicts we have checked, and an essay would have to earn each one.
History: how far was America's absence to blame for the League of Nations' failure?
- Weak (a list): "The League failed because of the absence of the USA, the Great Depression, and the Manchurian and Abyssinian crises."
- Strong: "The absence of the United States weakened the League from the start, but it was Britain and France's unwillingness to enforce effective sanctions over Abyssinia that turned weakness into failure, because it showed the League's leading members would not act for it."
It answers "how far" with a ranking and gives the essay its order.
English literature: ambition in Macbeth and Frankenstein
- Weak: "Macbeth and Frankenstein both present ambition, with similarities and differences."
- Strong, a compare and contrast thesis: "Both works punish ambition, but Shakespeare makes Macbeth's a crime against a king and a natural order, while Shelley makes Victor's a failure to take responsibility for what he has made; the danger moves from reaching too high to walking away from the result."
Education: should secondary schools ban phones for the whole school day?
Our working thesis was "Secondary schools should ban mobile phones because phones harm learning." The evidence changed it. Amez and Baert (2020), a review, found most published results point to a negative association between how often students use smartphones and their academic success, varying with method and measure. Beneito and Vicente-Chirivella (2022) report less bullying in two Spanish regions that banned phones in schools from 2015, and higher maths and science scores in one of them. Goodyear et al. (2025), across 30 English secondary schools, found no evidence that restrictive policies went with better wellbeing or less phone use overall, though pupils used phones less during the school day.
- Strong, an argumentative thesis in two sentences: "Heavy smartphone use is linked with lower attainment, and one Spanish region's ban was followed by better test scores, but a study of 30 English schools found no link between restrictive rules and better wellbeing. Schools have a sound case for keeping phones out of lessons, then, but not yet for promising that a whole-day ban will help pupils learn or feel better."
With mixed evidence, the limit needs its own sentence.
How EdCitation helps a thesis stand up
For the evidence under a thesis, EdCitation is the best tool we know of: it looks each source up in the publisher's record instead of writing one, which no chatbot can promise. We ran the free tools on 26 September 2026.
Find sources: is there evidence for the claim?
Find sources searched "smartphone use and academic performance" and returned 186,694 results, led by Amez and Baert's review (cited 266 times), then a 2019 study by Baert and colleagues asking whether the link is correlation or cause, the very objection this thesis must meet. The narrower "school mobile phone ban student attainment" returned 2,936, led by the Spanish study; the English one came seventh, and at least three of the first eight were off the topic, among them a study of phone sellers in Kigali. Read titles, not rank: a thin result may mean the claim is ahead of the evidence.
Cite a source: the entry
Cite a source built this APA 7 entry from Crossref's record, and screened it for retraction (none found):
Beneito, P., & Vicente-Chirivella, Ó. (2022). Banning mobile phones in schools: Evidence from regional-level policies in Spain. Applied Economic Analysis, 30(90), 153–175. https://doi.org/10.1108/aea-05-2021-0112
Quoting a finding like this or putting it in your own words is covered in paraphrase, quote or summarise.
Check your paper: does the thesis answer the brief?
We ran Check your paper on the First Paper Assignment from MIT's The Rise of Modern Science (Kaiser & Jones, 2010a), a brief comparing two seventeenth-century writers, George Starkey and Robert Boyle. It returned four rules, each with its source sentence: line spacing 2 ×, page count 4 to 5 pages, word count 1,200 to 1,500 words, and a reference list, required. Ten sentences came under "What it asks you to do, which no rule can test", including "You should articulate a clear thesis or argument, which you defend with specific examples from the readings and lectures."
The task sentence, from "Using two of the primary sources" to "evaluate the conventional wisdom", was among them, whole. The two questions that set the comparison, how the texts resemble each other and how they differ, came back in neither list, so read the brief yourself too. The brief also wants footnotes, which Cite a source does not make: its Chicago is the 18th edition's author-date style.
Theoretics QA: the finished essay against the brief
Theoretics QA, part of Max at $24 a month, judges the finished essay against its own brief, quoting the essay, and rewrites nothing. References from a file, in Pro at $8 a month, checks every reference and matches each citation to the list. See pricing. No tool can promise a mark.
Quick questions
How long should a thesis statement be?
Usually one sentence. Indiana allows one or two, and Toronto two or three, or a paragraph for a complex argument.
Where does the thesis statement go in an essay?
Most guides put the thesis statement at the end of the introduction, often the end of the first paragraph; Toronto says there is no rigid rule.
Can a thesis statement be a question?
No. LSBU says a thesis statement is not a question, and UMGC advises against framing it as one; it is your answer to the question.
Can my thesis change after I start writing?
Yes. UNC, Southampton and Toronto all expect a working thesis to be revised as the essay shows what it can prove.
Can EdCitation write my thesis statement?
No. EdCitation does not write thesis statements or any other text in an essay. Check your paper sets out the brief your thesis has to answer, free, and Theoretics QA (Max) weighs the finished essay against that brief.
References
- Amez, S., & Baert, S. (2020). Smartphone use and academic performance: A literature review. International Journal of Educational Research, 103, Article 101618. https://doi.org/10.1016/j.ijer.2020.101618
- Beneito, P., & Vicente-Chirivella, Ó. (2022). Banning mobile phones in schools: Evidence from regional-level policies in Spain. Applied Economic Analysis, 30(90), 153–175. https://doi.org/10.1108/aea-05-2021-0112
- Goodyear, V. A., Randhawa, A., Adab, P., Al-Janabi, H., Fenton, S., Jones, K., Michail, M., Morrison, B., Patterson, P., Quinlan, J., Sitch, A., Twardochleb, R., Wade, M., & Pallan, M. (2025). School phone policies and their association with mental wellbeing, phone use, and social media use (SMART Schools): A cross-sectional observational study. The Lancet Regional Health – Europe, 51, Article 101211. https://doi.org/10.1016/j.lanepe.2025.101211
- Harvard College Writing Center. (n.d.). Thesis. Harvard University. https://writingcenter.fas.harvard.edu/thesis
- Indiana University Bloomington Writing Tutorial Services. (n.d.). How to write a thesis statement. https://wts.indiana.edu/writing-guides/how-to-write-a-thesis-statement.html
- Kaiser, D., & Jones, D. (2010a). First paper assignment [Course assignment]. STS.003 The Rise of Modern Science, Fall 2010. MIT OpenCourseWare. https://ocw.mit.edu/courses/sts-003-the-rise-of-modern-science-fall-2010/pages/assignments/assn1/
- Kaiser, D., & Jones, D. (2010b). Guidelines for writing papers [Course handout]. STS.003 The Rise of Modern Science, Fall 2010. MIT OpenCourseWare. https://ocw.mit.edu/courses/sts-003-the-rise-of-modern-science-fall-2010/pages/assignments/assn1/guidelines/
- London South Bank University Library. (2026, April 29). State your overall point (the "thesis statement") in the introduction. Mini-module: Quick guide to critical writing. https://library.lsbu.ac.uk/c.php?g=715681&p=5182880
- Procter, M. (n.d.). Using thesis statements. Writing Advice, University of Toronto. https://advice.writing.utoronto.ca/planning/thesis-statements/
- Purdue Online Writing Lab. (n.d.). Tips and examples for writing thesis statements. Purdue University. https://owl.purdue.edu/owl/general_writing/the_writing_process/thesis_statement_tips.html
- University of Hull Library. (2026, September 9). Introductions. Essay writing. https://libguides.hull.ac.uk/essays/intros
- University of Maryland Global Campus. (2022). Thesis statement and controlling idea. Online guide to writing and research. https://www.umgc.edu/current-students/learning-resources/writing-center/online-guide-to-writing/tutorial/chapter2/ch2-10
- University of North Carolina at Chapel Hill Writing Center. (n.d.-a). Comparing and contrasting. https://writingcenter.unc.edu/tips-and-tools/comparing-and-contrasting/
- University of North Carolina at Chapel Hill Writing Center. (n.d.-b). Thesis statements. https://writingcenter.unc.edu/tips-and-tools/thesis-statements/
- University of Sheffield. (n.d.). How to develop an academic argument. StudySkills@Sheffield. https://sheffield.ac.uk/study-skills/writing/critical/argument
- University of Southampton Library. (2026, January 15). Thesis statements. Crafting the introduction. https://library.soton.ac.uk/writing_introductions/thesisstatements