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4.2 Research hypotheses

4.2.1 What is a hypothesis?

A hypothesis is a tentative answer to a research problem that is advanced so that it can be tested.

Source: unit author

When do I use a hypothesis?

It is appropriate to use a hypothesis when you are testing a theory. Your immediate answer to this may be 'I'm not testing a theory'; however, remember that our definition of theory is very broad - 'an idea about how things relate to each other'. If you have an expectation of how your research question will be answered (the outcome) then it is fair to say you have a theory in mind. If you ask of your research question 'What is the expected outcome?' and have an answer, you can ask why? What is my thinking behind this prediction? This is essentially the theory that you will be testing.

If you are not able to predict the answer to your question then your approach is not one of theory testing and you should not proceed with developing hypotheses to test. Your research questions remain as such. This will be the case if your research is descriptive or exploratory in nature.

Which of the example research questions stated in 4.1 above do you think could be restated as hypotheses?

When is the best time of year to translocate a meadow grassland from its original site in Surrey, south-east England to a new site?
Yes, there is a narrow question to be addressed to which a tentative answer could be suggested. This research question is suitable for testing as a hypothesis.

How does applying fertiliser affect the yield of a wheat crop grown on the North Downs in Kent?
Yes, again the question is amenable to testing.

What are the implications of de-regulating a hitherto controlled market for a staple food commodity on producers and consumers in a named region of a country?
This appears to be a more exploratory research question. However, if we have knowledge of some likely outcomes, these could be stated as hypotheses and tested.

Why do residents of a named village object to the siting of wind turbines 2 km from their homes?
This is a 'why' question which appears exploratory in nature- we do not know at the outset the nature of residents objections.

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Developing a hypothesis from a research question

Our definition of a hypothesis stresses that it can be tested. To meet this criterion the hypothesis must be operationalised - that is the concepts employed in the hypothesis must be measurable.

Developing hypotheses requires that you identify one character, variable or descriptor of a sampling unit that causes, affects, or has an influence on, another character, variable or descriptor of the same or other sampling units. The character, variable or descriptor that affects other variables or sampling units is called the independent variable. The character, variable or descriptor which is affected by the independent variable is called the dependent variable or response variable.

Note that although for the purposes of research methodology some variables may be called 'dependent' when investigating their relationship with other 'independent' variables, this does not imply the existence of a causal (as compared with associative) relationship unless strict rules of research design are followed. This issue is discussed in more detail later in the module.

4.2.2 Good hypotheses

There are two criteria for good hypotheses. One, hypotheses are statements about relationships between variables. Two, hypotheses carry clear implications for testing the stated relationships. These criteria mean, then, that hypothesis statements contain two or more variables that are measurable or potentially measurable and that they specify how the variables are related.

Source: Dixon et al (1987) p. 40.

Diagramming hypotheses

Diagramming hypotheses is a useful technique to help clarify your thinking.

Usually a hypothesis takes the form 'X causes Y' or 'X is related to Y'.

For example, the first hypothesis stated above could be represented by a diagram as follows

The two variables, or concepts are in boxes that are linked by an arrow going from one concept to the other. The arrow indicates that one variable (financial resources) does something to the other variable (adoption of new technology).

The plus sign indicates that the relationship is seen as positive, that is more of the one will lead to more of the other. Not all concepts have a positive relationship.

Once you get used to forming hypotheses and making diagrams then you can explore new patterns involving more than two concepts. For example:

In this case two concepts, finance and distance from market, are related as independent concepts to the dependent concept, adoption of technology. One of the independent concepts is positively related and the other negatively related to the dependent concept.

There are endless possibilities. Most research projects deal only with one small area of the diagram. But it is often useful to make a diagram of more than you plan to study in order to show where your research fits into the larger frame of things and to help you to identify factors which may have to be taken into account (these could be integrated into your conceptual map).

Research without hypotheses

In exploratory research our base knowledge of a subject may be so low that we cannot formulate meaningful hypotheses. Nonetheless, exploratory research should be guided by a clear sense of purpose. Instead of hypotheses, the design for the exploratory study should state its purpose, or research objectives as well as criteria by which the exploration will be judged successful.

For example, if we are trying to encourage farmers to make use of compost, we may first need to know the social structure or social norms of the farming community before we can begin making meaningful hypotheses about which individuals will influence the decision and the factors they consider when making their decision. We can state that our exploratory study would have the purpose of generating hypotheses about personal characteristics which correlate with the adoption/rejection of composting, the composition of the decision-making unit, and the factors which influence the decision either to adopt or reject. Success would be measured in terms of generating testable hypotheses.

Interpretative research, which seeks to develop knowledge through understanding meaning, does not usually proceed with hypotheses.