How to Narrow Down Your Thesis or Dissertation Topic

Prewriting can help you narrow down your thesis.
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Writing a thesis or dissertation can seem like a monumental task, but the best way to ensure that your project goes well is to get the question right. The research question is the topic, and the question must be narrow enough for you to collect and analyze data, qualitative or quantitative, to answer in 50 to 100 pages of text. Of course, you don’t want just any simple question, but one that is both interesting and useful to your field.

Make a list of questions in your subject area that you would like an expert to answer for you. This list should be your “wish list” of things that should be known in your field. Spend time on this list; you are more likely to find a great topic if you really stretch your imagination at this point. For example, a student of energy policy might start with a list of questions like "What policies are best to decrease energy consumption?" and "How can energy policy reduce pollution?"

Come up with a set of propositions for as many questions as you can. You will find that most questions result in propositions that don’t answer the whole question or are still too broad to research. This is to be expected, and the process of developing propositions helps you narrow your topics down to a single question that is manageable for your thesis or dissertation.

Let's say you started with the question "What policies are best to decrease energy consumption?" You might make the following propositions: a) Policies that increase the cost of energy consumption might decrease consumption, b) Policies that provide information about environmental effects might reduce consumption, and c) Policies that increase technological efficiency might decrease consumption. Note that these are all still too broad to research.

Identify the propositions in your lists that you can relate to a method or theory in your field. You are likely so familiar with theories that they are already underlying your questions or propositions. For example, a student with the proposition “Policies that increase the cost of energy consumption might reduce consumption” relates the proposition with the economic theory that they were already considering: “as prices increase, demand decreases”.

Determine what information will be needed to evaluate these propositions in light of the theory you identified as relating to the propositions. This is an important step; many good questions cannot be answered because the data are impossible or too expensive to obtain. However, you should be able to identify the information needed and how you might be able to get it. If you cannot figure out what information is needed to support or refute your proposition, it is too broad. Try thinking about subsequent questions and how you might answer them.

For example, to evaluate “Policies that increase the cost of energy consumption might reduce consumption”, a researcher will need to identify a specific policy or policy type and probably a particular fuel; this will become clear when trying to identify information needed. What policy? What cost? What energy? To illustrate, the researcher might decide to look at changes in state and federal diesel taxes and the consumption of diesel; all of these are readily available as archival data. The data needed are diesel consumption by state, federal, and state tax levels, and any other variables needed to support theory--likely some macroeconomic indicators that might indicate alternative explanations.

Select a few promising propositions based on the information and theory you have determined is appropriate. Rephrase them as questions.

For example, a researcher looking at the relationship between cost and consumption of fuel might ultimately ask if increases in state diesel taxes from 1985 to 1995 decreased diesel consumption.

Check the academic literature in your field to ensure that no one has already answered your question(s). Then, see your adviser with your short list of specific research questions.

  • If your topic is too general, you will not be able to manage the answer in the time and space allotted for thesis or dissertation work.
  • If your topic is not grounded in theory, you may have difficulty gaining approval from your committee.
  • Be picky about your research topic. You are the expert answering your research question, and you will be living with this question for a long time. Make sure you are becoming an expert in something that really interests you.
  • If you simply can’t make progress in narrowing your topic or you hit a dead end, review recent literature for “further research needed” statements.
  • 1 “Proposals that work: a guide for planning dissertations and grant proposals”; Locke, Lawrence F., Waneen Wyrick Spirduso, and Stephen J. Silverman; 2007
  • 2 “Destination dissertation: a traveler's guide to a done dissertation”; Foss, Sonja K., and William Joseph Condon Waters; 2007

Jae Chapman is a sustainability enthusiast who has been writing since 2006. She writes for various websites with a focus on the environment, food, fitness, computer software and other practical topics. She holds a Master of Science in engineering from the Georgia Institute of Technology.