Formulating hypotheses, which are defined as propositions set forth to explain a group of facts or phenomena, is a fundamental component to any research scholarship. Hypotheses lay out the central arguments that will be tested and either verified or rejected in the body of a paper. Papers may address multiple competing or supporting hypotheses in order to account for the full spectrum of explanations that could account for the phenomenon being studied. As such, hypotheses often include statements about a presumed impact of an independent variable on a dependent variable.
Hypotheses should not emanate from preconceived perceptions about a given relationship between variables, but rather should come about as a product of research. Thus, hypotheses should be formed after developing an understanding of the relevant literature to a given topic rather than before conducting research. Beginning research with a specific argument in mind can lead to discounting other evidence that could either run counter to this preconceived argument or could point to other potential explanations.
There are a number of different types of hypotheses utilized in political science research:
- Null hypothesis: states that there is no relationship between two concepts
- Correlative hypothesis: states that there is a relationship, between two or more concepts or variables, but doesn’t specify the nature of a relationship
- Directional hypothesis: states the nature of the relationship between concepts or variables. These types of relationships can include positive, negative (inverse), high or low levels of influence, etc.
- Causal hypothesis: states that one variable causes the other
A good hypothesis should be both correlative and directional and most hypotheses in political science research will also be causal, asserting the impact of an independent variable on a dependent variable.
There are a number of additional considerations that must be taken into account in order to make a hypothesis as strong as possible:
- Hypotheses must be falsifiable, that is able to be empirically tested. They cannot attribute causation to something like a supernatural entity whose existence can neither be proven nor denied.
- Hypotheses must be internally consistent, that is that they must be proving what they claim to be proving and must not contain any logical or analytical contradiction
- Hypotheses must have clearly defined outcomes (dependent variables) that are both dependent and vary based on the dependent variable.
- Hypotheses must be general and should aim to explain as much as possible with as little as possible. As such, hypotheses should have as few exceptions as possible and should not rely on amorphous concepts like ‘national interest.’
- Hypotheses must be empirical statements that are propositions about relationships that exist in the real world.
- Hypotheses must be plausible (there must be a logical reason why they might be true) and should be specific (the relationship between variables must be expressed as explicitly as possible) and directional.
- Fearon, James D. 1991. Counterfactuals and Hypothesis Testing in Political Science. World Politics 43 (2): 169-195.
Abstract: “Scholars in comparative politics and international relations routinely evaluate causal hypotheses by referring to counterfactual cases where a hypothesized causal factor is supposed to have been absent. The methodological status and the viability of this very common procedure are unclear and are worth examining. How does the strategy of counterfactual argument relate, if at all, to methods of hypothesis testing based on the comparison of actual cases, such as regression analysis or Mill’s Method of Difference? Are counterfactual thought experiments a viable means of assessing hypotheses about national and international outcomes, or are they methodologically invalid in principle? The paper addresses the first question in some detail and begins discussion of the second. Examples from work on the causes of World War I, the nonoccurrence of World War III, social revolutions, the breakdown of democratic regimes in Latin America, and the origins of fascism and corporatism in Europe illustrate the use, problems and potential of counterfactual argument in small-N-oriented political science research.” – Jstor.org
- King, Gary, Robert Owen Keohane, and Sidney Verba. 1994. Chapter 1 and 3. Designing social inquiry: scientific inference in qualitative research. Princeton, NJ: Princeton University Press.
- Marschall, Melissa J. 2002. Methods of Political Science Formulating Hypotheses. University of Illinois at Chicago Department of Political Science.
- Palazzolo, David and Dave Roberts. 2010. What is a Good Hypothesis? University of Richmond Writing Center.