The cause of an acute exacerbation is usually unknown, although some acute exacerbations result from bacterial or viral infections. Smoking, irritative inhalational exposure, and high levels of air pollution also contribute.
Operational Definition. The operational definition of a variable is the specific way in which it is measured in that study. Another study might measure the same conceptual measure differently.If you were studying ways of helping people stop smoking, smoking cessation would be an outcome measure (dependent variable).ou could measure smoking cessation as a person not smoking a cigarette for 1 month, or as a person who has not smoked in a year, or a 50% reduction in the number of cigarettes smoked. Clearly the operational definition of the dependent variable is an important step in the design of the study.
Operational definition. From Wikipedia, the free encyclopedia. An operational definition is a result of the process of operationalization and is used to define something (e.g. a variable, term, or object) in terms of a process (or set of validation tests) needed to determine its existence, duration, and quantity.andervert (1980/1988) described in scientific detail a simple, every day illustration of an operational definition in terms of making a cake (i.e., its recipe is an operational definition used in a specialized laboratory known as the household kitchen).