Undergraduate Thesis Formatting Guide (Series) 02: Heading Hierarchy and Body Styles — Why “Consistency” Matters More Than “Looking Nice”

In an undergraduate thesis, the heading system performs three tasks:

1. Navigation: let reviewers locate what they care about without reading everything
2. Structure proof: show what you are talking about → how you expand it → how deep the expansion goes
3. Automation: allow TOC, bookmarks, and cross-references to be generated and updated reliably

Once headings stop being a “system” and become “bold/resize whenever it feels right”, all three tasks fail at once.

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For many reviewers, the most common actions are not reading — they are:

• Scan: scan headings to judge whether the structure is complete
• Jump: jump via TOC/bookmarks into a chapter
• Mark: annotate key paragraphs, underline, tag questions
• Return: jump back to earlier definitions/variables/assumptions (which depends on stable location cues)

Consistency makes these actions cheap and error‑resistant.

“Looking nice” is self‑expression — but a thesis is not a poster.

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3.1 Headings are not decoration; they are hierarchy signals

Without even reading the heading text, a reader should be able to tell:

• which headings are at the same level
• which are subordinate sections
• how deep the hierarchy goes (and whether it becomes overly fragmented)

So the key is not a specific point size. It is: same level looks the same; different levels look different.

3.2 The minimal sufficient conditions for a usable visual hierarchy

You don’t need advanced design. Meeting these three rules is enough:

1. Headings at the same level must look identical (font/size/bold/spacing/numbering rules)
2. Different levels must be distinguishable (at least one stable difference in size/bold/indent/before-after spacing)
3. Keep depth under control (a common undergraduate issue is an over-deep hierarchy that turns the TOC into “tree roots”)

In practice, 2–3 levels are common for undergraduate theses; 4+ levels often indicates you are using structure as a substitute for argument.

3.3 Numbering is for location, not “formality”

Numbering such as 1, 1.1, 1.1.1 reduces discussion and review cost:

“What is your evidence for that sentence in 2.3.1?”

Whether numbering is required depends on the school template, but the reason it exists is stable: lower the cost of precise referencing.

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Body formatting (font, line spacing, paragraph spacing, indents, alignment) looks like small details, but it determines whether the thesis supports three “working” properties:

1. Readable for long sessions: line length, spacing, and paragraph rhythm reduce fatigue
2. Annotatable: whitespace and consistency prevent comments from breaking the layout
3. Scannable and locatable: clear paragraph boundaries help people find information quickly

That’s why many universities enforce uniform styles even at the expense of “beauty”: it serves review and archiving workflows.

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The most common disasters are not “choosing the wrong font size”, but:

• manually adjusting paragraph by paragraph (“this looks weird, add a blank line; that needs two spaces”)
• copy‑pasting from multiple sources (importing different fonts/spacing)
• using spaces/returns to simulate layout (making TOC, page numbers, and alignment uncontrollable)

These tricks look okay short‑term, but cause:

• unreliable TOC generation
• layout breakage when exporting to PDF or printing
• “global consistency checks” becoming manual labor

So the point is not “use font X”, but don’t fight the Styles system with manual hacks.

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6.1 First-line indent: it tells readers “a new unit of thought starts here”

Indenting marks paragraph boundaries and supports scanning and revisiting.

If spacing/indent/alignment are all inconsistent, readers lose paragraph rhythm and reading cost skyrockets.

Principle: choose one primary boundary signal (indent or paragraph spacing) and apply it consistently; don’t mix signals into noise.

6.2 Line spacing and paragraph spacing: they reserve room for annotation and rereading

A thesis is not a novel; reviewers write, underline, and mark symbols.

Too tight: annotations collide. Too loose: information density drops and page count inflates.

Principle: optimize for annotation and rereading, not for “looking airy”.

6.3 Justified vs left-aligned: stable boundaries vs weird word spacing

Side effects differ by language: full justification in English can produce large gaps.

For undergraduate theses, the priority is stable readability without distracting spacing.

Principle: follow the official template; if there’s no hard rule, pick the option that reads more consistently.

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This is the natural entry for a checker: we don’t argue aesthetics; we verify minimum usability for a working document.

7.1 Heading hierarchy acceptance criteria

• Same-level consistency: same-level headings use exactly the same style (font/size/bold/spacing/numbering)
• Cross-level distinction: different levels differ in at least one stable attribute
• Depth control: detect overly deep hierarchies (e.g., 1.2.3.4) that fragment the TOC
• Numbering continuity: numbering is continuous (no gaps/duplicates)
• TOC‑ready: headings use heading styles instead of manual bolding

7.2 Body style acceptance criteria

• Font consistency: the main body uses one primary font (excluding necessary English/symbol fonts)
• Paragraph boundary consistency: indent/spacing strategy is consistent throughout
• Outlier detection: detect a few paragraphs that suddenly change size/spacing (often from paste)
• Blank-line abuse: detect using extra blank lines to simulate spacing
• Invisible character risk: detect heavy use of manual spaces/tabs for alignment (fragile in exports)

Note: we still avoid school-specific numbers here; we verify consistency and usability. Numeric parameters live in the school template.