Aids

Key terms

Definitions for key terms are provided in the Glossary.

Main points

1. Concepts are mental images we agree upon and use to describe what we want to talk about. Social scientists also use the word construct to describe a concept.
2. Concepts are used at all stages of research - to state the question for investigation, for describing variables, and for expressing findings and conclusions. Concepts also are the basis of communication among social scientists.
3. A theory expresses a logical and organized set of relationships among concepts. Theories are based on research findings but go beyond any specific results. A theory integrates existing knowledge and provides an explanation for a set of relationships.
4. Variables are composed of two or more attributes, each of which differs numerically or in terms of qualities.
5. Attributes are the characteristics of variables. The variable gender, for example, is composed of two attributes: male and female.
6. Hypotheses are tentative statements of expected relationships among variables. Hypotheses are generally derived from a theoretical framework, but may also be derived from empirical relationships among variables.
7. In formulating a hypothesis, the variable that is presumed to influence another variable is designated as the independent variable. The variable affected by the independent variable is designated as the dependent variable.
8. Hypotheses are usually expressed as positive or negative. A positive hypothesis states that as the independent variable increases so does the dependent variable. A negative hypothesis says that an increase in the independent variable is associated with a decrease in the dependent variable. Others forms of hypotheses express curvilinear or no relationship. A curvilinear relationship is one in which the association goes first in a positive or negative direction and then reverses to the other direction. When two variables show no relationship they are said to be independent of one another.
9. Two important forms of logic used in research are inductive and deductive reasoning. Inductive logic involves reasoning from data to a conclusion. Deductive logic is based on reasoning from a general statement to a predicted set of observations.
10. Both forms of logic are used in deriving and testing a hypothesis. Deductive logic is used to derive the hypotheses from statements the investigator believes to be true, while inductive logic is used to test whether or not the hypothesis is supported by the data.
11. In a causal relationship, the independent variable is presumed to cause changes in the dependent variable.
12. To establish a cause and effect relationship, an investigator must show that the independent variable precedes the dependent variable; that there is a strong relationship between the two variables; and that the observed relationship cannot be explained by the influence of any other variable that could cause changes in both the independent and dependent variables.
13. Cause and effect relationships are extremely difficult to confirm. Researchers, therefore, are extremely cautious in making any cause and effect statements.