Blackwell Reference Online

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Research involves identification and description of characteristics of organisms, objects, events, and locations. When these characteristics can take on different values (e.g., when they differ between people or from one time to another for the same person), they are referred to as variables . The variables involved in any particular research study are determined by the interests and intentions of the researcher. Much research focuses on the relationships between variables, particularly causal relationships . In such research, independent variables are the presumed causes whose effects are measured via changes in the value of dependent variables . Independent variables are temporally or theoretically prior to (and therefore independent of) dependent variables. For example, the manner in which the prosecutor and defense attorney present their closing arguments to a jury precedes the jury's deliberations and verdict, and so may influence them. Thus, various aspects of the closing arguments might be viewed as independent variables. According to Cohen et al. (2003) , there are four requirements for the treatment of a variable X as a cause (or independent variable) of variable Y (the effect or dependent variable): 1 X precedes Y in time (temporal precedence). 2 Some mechanism whereby this causal effect operates can be posited (causal mechanism). 3 A change in the ... log in or subscribe to read full text