04 VARIABEL PENELITIAN KULIAH 04 METODOLOGI PENELITIAN STATISTIK

04 VARIABEL PENELITIAN KULIAH 04 METODOLOGI PENELITIAN & STATISTIK DESKRIPTIF (ARIES YULIANTO, S. PSI. , M. SI) CHAPTER 3 DEFINING AND MEASURING VARIABLES

CONSTRUCTS AND OPERATIONAL DEFINITIONS • Step 3 of the research process: How researchers define and measure • • variables. Variables as characteristics or conditions that change or have different values for different individuals. (p. 53) To evaluate differences or changes in variables, it is essential that we are able to measure them. Theories and Constructs In attempting to explain and predict behavior, scientists and philosophers often develop theories that contain hypothetical mechanisms and intangible elements. Theory is a set of statements about the mechanisms underlying a particular behavior. Theories help organize and unify different observations of the behavior and its relationship with other variables. A good theory generates predictions about the behavior. Constructs are hypothetical attributes or mechanisms that help explain and predict behavior in a theory.

CONSTRUCTS AND OPERATIONAL DEFINITIONS • Operational Definitions (p. 54) = a procedure for indirectly measuring and defining a variable that cannot be observed or measured directly. • Limitations of operational Definitions: ü an operational definition is not the same as the construct itself. ü The primary limitation of an operational definition is that there is not a one -to-one relationship between the variable that is being measured and the actual measurements produced by the operational definition. ü First, it is easy for operational definitions to leave out important components of a construct. It is possible, for example, to define depression in terms of behavioral symptoms (social withdrawal, insomnia, etc. ). However, behavior represents only a part of the total construct. ü Second, operational definitions often include extra components that are not part of the construct being measured.

CONSTRUCTS AND OPERATIONAL DEFINITIONS Using operational Definitions (p. 55) • Whenever the variables in a research study are hypothetical constructs, you must use operational definitions to define and measure the variables. Usually, however, this does not mean creating your own operational definition. • The best method of determining how a variable should be measured is to consult previous research involving the same variable. • However, keep in mind that any measurement procedure, particularly an operational definition, is simply an attempt to classify the variable being considered. • Other measurement procedures are always possible and may provide a better way to define and measure the variable. • two general criteria used to evaluate the quality of a measurement procedure, especially an operational definition: validity & reliability.

VALIDITY AND RELIABILITY OF MEASUREMENT 1. validity of Measurement p. 58 = is the degree to which the measurement process measures the variable that it claims to measure. The first criterion for evaluating a measurement procedure is validity. To establish validity, you must demonstrate that the measurement procedure is actually measuring what it claims to be measuring. Does the measurement procedure accurately capture the variable that it is supposed to measure? 2. Reliability of Measurement (p. 62) = is the stability or consistency of the measurement. A measurement procedure is said to have reliability if it produces identical (or nearly identical) results when it is used repeatedly to measure the same individual under the same conditions. The relationship between reliability and validity (p. 64) these two factors are partially related and partially independent. They are related to each other in that reliability is a prerequisite for validity; that is, a measurement procedure cannot be valid unless it is reliable.

SCALES OF MEASUREMENT p. 64 4 different types of measurement scales: 1. nominal, 2. ordinal, 3. interval, 4. ratio.

MODALITIES OF MEASUREMENT p. 69 1. self-report Measures 2. physiological Measures 3. behavioral Measures