When measure a complex concept such as love, intelligence, motivation, there is no direct measure as when we measure height, weight. Those complex concepts are also linked to behavior. The construct can be referred as hypothetical constructs. “Hypothetical” because they are inferred from theories and other behavior, and “constructs” because they must be constructed by using a database of observations that can be measured. (clayton)
Practically the construct is defined by how it is measured. This is called an operational definition.
The meaning of our study rests on how we objectively observe the construct or behavior of interest. Thus, developing a reliable and valid set of procedures for measuring our variables is crucial for the validity of any research study. Good operational definitions require that we first specify our constructs .Developing reliable and valid operations is the last step of specifying constructs when we are designing our own studies.
Reliability and validity are issues for all operational definitions. We want accurate and reliable observations and we want our observations to validly reflect the variable of interest. If choosing an existing coding scheme, look for good interrater reliability. Remember that the more complex the behavior that is recorded, the more difficult it is to achieve good interrater reliability. Coding schemes that have been successfully used in other studies demonstrate good construct validity. If you are developing your own measure, be sure to assess interrater reliability. At minimum, you should have good content validity.
| | | | | | | | | | | | | | | | | | | | | | | | |The meaning of our study depends on how well we measure the variables of interest. Operational definitions are the procedures | |that translate our ideas into specific measurements. | |When possible, select measures or procedures available in published literature. | |Specific measurement procedures vary in observational, survey, and experimental research. In all cases, good operational | |definitions require a great deal of thought about what you want to know/measure. | |All operational definitions require clear directions and language that all participants and observers can understand. | |...
References: Cronbach, L. J. & Meehl, P. E. (1955). Construct validity in psychological tests. Psychological Bulletin, 52, 281-302.
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