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.
The operational definition of an empirical term (i.e., a descriptor of some element of physical experience) is the description of a specific process, or set of validation tests, accessible to more persons than the definer (i.e., said to be publicly accessible), whereby it is (or can be) repeatedly measured or tested.herefore, weight of an object labels an operational definition which is a nonspecific process.) But an historical event (e.g., the process of taking my weight last Tuesday) cannot be an operational definition because it cannot be repeated.