Chapter 4: Building an Arguable Thesis

What You Will Make

Write a working thesis and an evidence note explaining why it is defensible. A thesis should help you decide what belongs in the essay. It may change when you examine a serious objection.

State the Answer at the Right Scale

Distinguish a result from its interpretation. A number can be accurately copied yet used to support the wrong conclusion. Qualify the part that is uncertain rather than making every sentence vague.

Fictional teaching case: This lesson uses the invented campus-transit records in Chapter 1. Record labels and numbers are practice material, not real research to cite or submit.

Revise an Overclaim

First version: “The service change improved access for all students because ridership rose.” This moves from trips to people, from a before/after difference to a causal explanation, and from a count to universal access.

Working thesis: “The dossier records greater weekday use after the change, but the unchanged last departure leaves the reported late-class timetable gap unresolved; it does not establish improved access for all students.”

Record A supports increased boardings. Records B and C support the timetable problem described by those respondents. None of the records identifies every student’s experience. The qualification makes the conclusion more accurate while preserving a clear judgement.

The thesis is not merely “more research is needed.” It already explains what the current evidence supports and why one attractive conclusion goes too far.

Try It Yourself

Underline the central claim in your draft. Circle words such as “all,” “proves,” “causes,” and “always,” then ask what evidence each would require. Keep strong wording when justified; replace it when the support is narrower.

Write a plausible objection. For the dossier, a reader may argue that greater use is still a benefit. Concede that point while explaining why it does not resolve the particular evening-access question.

Check Your Work

• Does the thesis answer your research question?
• Can you identify support for each important clause?
• Does it distinguish observation, explanation, and evaluation?
• Does the qualification improve precision rather than hide the answer?

Use the revised thesis to select and order the essay’s main points.

Source Guidance

A thesis needs a scope and interpretation that the evidence can support. (Harvard College Writing Center)