Writing Research Questions and Hypotheses

Writing Research Questions and Hypotheses

The purpose of this module is to discuss research questions and research hypotheses and to provide definitions, comparisons and examples of both.

Learning Objectives

  • Define research question and research hypothesis
  • Explain the difference between a research question and a research hypothesis and describe the appropriate use of each
  • Describe the purpose of each and understand the importance of a well-developed question or hypothesis
  • Provide examples of research questions and research hypotheses


Once you have chosen your research topic or subject, you will need to decide how you will approach the research process – by formulating a hypothesis or developing a research question. This can be determined by starting with the following questions. Is there a significant body of knowledge already available about your subject that allows you to make a prediction about the results of your study before you begin? If so, you will be using a hypothesis. Or is your research more exploratory and investigative in nature and will require that you collect data and analyze results before drawing any conclusions? If this describes your research topic, you will be developing a research question. Understanding this difference and choosing the correct approach will drive the rest of your research project. The following sections further describe research questions and hypotheses and provide examples of each.

Research Questions

  • Used to analyze and investigate a topic. It is written as a question and is inquisitive in nature.
  • A properly written question will be clear and concise. It should contain the topic being studied (purpose), the variable(s), and the population.
  • Three main types of questions:
    • Causal Questions – Compares two or more phenomena and determines if a relationship exists. Often called relationship research questions. Example: Does the amount of calcium in the diet of elementary school children effect the number of cavities they have per year?
    • Descriptive Questions – Seek to describe a phenomena and often study “how much”, “how often”, or “what is the change”. Example: How often do college-aged students use Twitter?
    • Comparative Questions – Aim to examine the difference between two or more groups in relation to one or more variables. The questions often begin with “What is the difference in...”.   Example: What is the difference in caloric intake of high school girls and boys?
  • The type of research question will influence the research design.
  • Once data has been collected, it will be analyzed and conclusions can be made.


  • It is predictive in nature and typically used when significant knowledge already exists on the subject which allows the prediction to be made.
  • Data is then collected, analyzed, and used to support or negate the hypothesis, arriving at a definite conclusion at the end of the research.
  • It is always written as a statement and should be developed before any data is collected.
  • A complete hypothesis should include: the variables, the population, and the predicted relationship between the variables.
  • Commonly used in quantitative research, but not qualitative research which often seeks answers to open-ended questions.
  • Examples: A company wellness program will decrease the number sick days claimed by employees.   Consuming vitamin C supplements will reduce the incidence of the common cold in teenagers.

The following video, Hypotheses vs. Research Questions, discusses how to choose whether to use a hypothesis or a question when creating a research project. It provides a definitions, a comparison of the two, and examples of each.


Suggested Readings

Bryman, A. (2012). Social research methods. Oxford university press.
Alon, U. (2009). How to choose a good scientific problem. Molecular Cell, 35, 726-728.
Cox, C. (2012). What makes for good research? [Editorial] International Journal of Ophthalmic Practice, 3(1), 3.
Creswell, J. W. (2002). Educational research: Planning, conducting, and evaluating quantitative. Prentice Hall.
Creswell, J. W. (2013). Research design: Qualitative, quantitative, and mixed methods approaches. Sage publications.
Isaac, S., & Michael, W. B. (1971). Handbook in research and evaluation.
Robson, C. (2002). Real world research (Vol. 2). Oxford: Blackwell publishers.
Taylor, D. (1999). Introduction to Research Methods. medicine, 319, 1618.

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