What is an engineering thesis, anyway?

A concise guide to a frequently unasked question


Understanding theses

If you’re doing a thesis-pattern graduate degree you need to produce a thesis. In fact, you will likely spend a year or more working on it, so it’s probably in your best interest to understand just exactly what a thesis is, sooner rather than later.

Here’s a working definition of “thesis” that will serve for this discussion:

thesis, n : a treatise advancing a new point of view resulting from research.

Treatise means you have to write it down (sorry). Advancing means that what you write is an argument — more on this later. A new point of view suggests that there is something novel about your work. And your argument results from research; that means the new point of view you’re advancing comes as the result of a scholarly or experimental process.

Around here we do engineering research. This generally falls into two categories:

Your thesis is therefore an argument that you have satisfactorily solved some engineering problem or have advanced scientific knowledge in some interesting way.

The actual format and organisation of your thesis document is ultimately between you and your supervisor. However, for an engineering or engineering science thesis the argument in the document must include satisfactory answers to four questions.

The engineering thesis

An engineering thesis is oriented towards engineering practice. Its four essential questions are:

  1. What is the engineering problem to be solved?

  2. In what sense are previous solutions to this problem unsatisfactory?

  3. What is my solution?

  4. How does my solution compare to previous solutions? What are its benefits and drawbacks?

The novelty in an engineering thesis is normally found in the solution to the problem. The problem should be general enough that its solution is interesting outside the immediate context of your thesis.

An engineering thesis that answers only questions 1 and 3 is really just an engineering experience report. This is simply not good enough — your work’s academic value comes from the rigorous evaluation of your solution and comparison with other solutions. You shouldn’t expect to graduate without satisfactory answers to questions 2 and 4, although people occasionally do.

The engineering science thesis

An engineering science thesis advances scientific knowledge in support of future solutions to engineering problems. That is, the scientific question asked is motivated by engineering needs. The four essential questions in this kind of thesis are:

  1. What is the question about the world that needs to be answered?

  2. In what sense are previous answers to this question inadequate?

  3. What is my answer to this question?

  4. How good is my answer in comparison to previous answers?

The “question about the world” is normally about an engineered system.

An exploratory thesis asks “what are the properties of system S”? Typically S is some system intended to solve an engineering problem, but whose properties are inadequately understood. The novelty in an exploratory thesis comes from the discovery and characterization of the interesting properties, and from the design and execution of the process by which they were observed. The evidence is partially in the form of the observed results and partially an argument that the observational process was appropriate.

An experimental thesis asks “is prediction P made by theory T accurate?” Prediction P must be interesting and non-trivial to test. The novelty in an experimental thesis comes from the design, execution and analysis of the experiment. The evidence is partially in the form of the results and partially a logical argument that the experiment adequately tests the prediction.

A theoretical thesis asks “what theory adequately explains observations O?” The novelty in a theoretical thesis is found in the theory itself. The evidence for its utility is normally its ability to explain the previously-unexplained observations and to make non-obvious predictions about other features of the world.

Some theses are exploratory, theoretical and experimental: that is, observations are made of a system, a theory is proposed which explains those observations, new predictions are made from this theory, and experiments are conducted to verify the predictions. This is probably overkill for Masters-level work, but may be appropriate at the Doctoral level.

How to position your thesis

A given piece of research can often be presented as any one of engineering, science-exploratory, science-theoretical or science-experimental. (For instance, consider the engineering science question about the world “what is an appropriate solution to engineering problem E?”) However, your thesis argument will generally be cleaner if you can figure out which of the four thesis types presented here is the closest fit. Try writing your argument out in each form and see how the different versions feel. If none of them feel right, think hard about whether you really have a clear thesis or if perhaps you need to change direction.

Greg Phillips

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