How To Write A Dissertation


Bedtime Reading For People Who Do Not Have Time To Sleep

By Doug Comer of Purdue University

To The Candidate:

So, you are preparing to write a Ph.D. dissertation in an experimental area of Computer Science. Unless you have written many formal documents before, you are in for a surprise: it's difficult!

There are two possible paths to success:

Here are a few guidelines that may help you when you finally get serious about writing. The list goes on forever; you probably won't want to read it all at once. But, please read it before you write anything.

The General Idea:

  1. A thesis is a hypothesis or conjecture.

  2. A PhD dissertation is a lengthy, formal document that argues in defense of a particular thesis. (So many people use the term "thesis" to refer to the document that a current dictionary now includes it as the third meaning of "thesis").

  3. Two important adjectives used to describe a dissertation are "original" and "substantial." The research performed to support a thesis must be both, and the dissertation must show it to be so. In particular, a dissertation highlights original contributions.

  4. The scientific method means starting with a hypothesis and then collecting evidence to support or deny it. Before one can write a dissertation defending a particular thesis, one must collect evidence that supports it. Thus, the most difficult aspect of writing a dissertation consists of organizing the evidence and associated discussions into a coherent form.

  5. The essence of a dissertation is critical thinking, not experimental data. Analysis and concepts form the heart of the work.

  6. A dissertation concentrates on principles: it states the lessons learned, and not merely the facts behind them.

  7. In general, every statement in a dissertation must be supported either by a reference to published scientific literature or by original work. Moreover, a dissertation does not repeat the details of critical thinking and analysis found in published sources; it uses the results as fact and refers the reader to the source for further details.

  8. Each sentence in a dissertation must be complete and correct in a grammatical sense. Moreover, a dissertation must satisfy the stringent rules of formal grammar (e.g., no contractions, no colloquialisms, no slurs, no undefined technical jargon, no hidden jokes, and no slang, even when such terms or phrases are in common use in the spoken language). Indeed, the writing in a dissertaton must be crystal clear. Shades of meaning matter; the terminology and prose must make fine distinctions. The words must convey exactly the meaning intended, nothing more and nothing less.

  9. Each statement in a dissertation must be correct and defensible in a logical and scientific sense. Moreover, the discussions in a dissertation must satisfy the most stringent rules of logic applied to mathematics and science.

What One Should Learn From The Exercise:

  1. All scientists need to communicate discoveries; the PhD dissertation provides training for communication with other scientists.

  2. Writing a dissertation requires a student to think deeply, to organize technical discussion, to muster arguments that will convince other scientists, and to follow rules for rigorous, formal presentation of the arguments and discussion.

A Rule Of Thumb:

    Good writing is essential in a dissertation. However, good writing cannot compensate for a paucity of ideas or concepts. Quite the contrary, a clear presentation always exposes weaknesses.

Definitions And Terminology:

  1. Each technical term used in a dissertation must be defined either by a reference to a previously published definition (for standard terms with their usual meaning) or by a precise, unambiguous definition that appears before the term is used (for a new term or a standard term used in an unusual way).

  2. Each term should be used in one and only one way throughout the dissertation.

  3. The easiest way to avoid a long series of definitions is to include a statement: "the terminology used throughout this document follows that given in [CITATION]." Then, only define exceptions.

  4. The introductory chapter can give the intuition (i.e., informal definitions) of terms provided they are defined more precisely later.

Terms And Phrases To Avoid:



Define Negation Early:

Grammar And Logic:

Focus On Results And Not The People/Circumstances In Which They Were Obtained:

Avoid Self-Assessment (both praise and criticism):

References To Extant Work:

Concept Vs. Instance:

Terminology For Concepts And Abstractions

Knowledge Vs. Data

Cause and Effect:

Drawing Only Warranted Conclusions:

Commerce and Science:

Politics And Science:

Canonical Organization:

Suggested Order For Writing:

Key To Success:

Parting thoughts: