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Research Methods Room

The constellations in this room are concerned with how you will be doing your research. There is a very wide range of research methods available to you, and you will have to spend some time deciding which method or methods are the most appropriate, both with regard to your topic and to the approach you have decided to take. If you are a student in the physical sciences then you will probably find you tend toward quantitative or positivist methods. If you are studying the social sciences then qualitative or interpretive methods may be more appropriate. But this is a generalization, and much of the really interesting and innovative research uses a blend of both qualitative and quantitative methods. As you study the constellations visible from this room, keep referring to the continuum on the left and see if you can spot your position on it, and if you might move along it.

Research methods > Experimental research design
Conical flasks

Research methods

Experimental research design

An experiment can be defined as:

“A rigorous controlled investigation of an activity where key factors are identified and manipulated to document their effects on an outcome” (Fenton and Pfleeger 1996).

“A procedure adopted or operation carried out to make a discovery, observation or test” (Oxford English Dictionary 2006).

This constellation aims to introduce some simple concepts associated with the design of an experiment. Designing an experiment would often take up a full year of study for an undergraduate university student. Here, we hope to introduce you to:

  • why you might want to conduct an experiment
  • some basic types of experimental design
  • generating research questions and hypotheses
  • variables and randomisation
  • ethics
  • validity
  • reliability

It is crucial to design an experiment before you begin, otherwise you might find that you do not produce valid, reliable results and that you may not be able to answer your research question. Your experiment will require the adoption of exact procedures which entail manipulating variables in the study, collecting precise measurements and analysing these using established statistical procedures. The data is likely to be quantitative and the statistical procedures are likely to place requirements on the way the research is conducted. You must have more than one piece of data - you can't say that something is better or faster if you have only tested it once!

Experiments are not just for scientists! Experiments are used in the fields of market research, education and psychology to name but a few.




1. Experiments are not just for scientists!
2. Why choose an experimental strategy?3. Why do experiments need designing?
4. Designing your experiment 5. Generating research questions
6. Developing research and scientific hypotheses
7. Dependent and independent variables
8. Extraneous and confounding variables
9. Experimental controls and randomisation10. Your variables and controls / randomisation
11. Resources for your experiment
12. Sample size at the design stage
13. Ethics at the design stage14. Validity
15. Reliability16. Review your design
17. Getting started checklists

Authors: Deborah Street and Olivia Billingham with contributions from Liz Falconer and Paul White, University of the West of England, Bristol.

Further reading