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Contamination control is the generic term for all activities aiming to control the existence, growth and proliferation of contamination in certain areas. Contamination control may refer to the atmosphere as well as to surfaces, to particulate matter as well as to microbes and to contamination prevention as well as to decontamination.
When estimating the effect of explanatory variables on an outcome by regression, controlled-for variables are included as inputs in order to separate their effects from the explanatory variables. [1] A limitation of controlling for variables is that a causal model is needed to identify important confounders (backdoor criterion is used for the ...
A variable in an experiment which is held constant in order to assess the relationship between multiple variables [a], is a control variable. [2] [3] A control variable is an element that is not changed throughout an experiment because its unchanging state allows better understanding of the relationship between the other variables being tested.
ISO 14698-1 was first written in 2003. ISO 14698-1 describes the principles and basic methodology for a formal system to assess and control biocontamination, where cleanroom technology is applied, in order that biocontamination in zones at risk can be monitored in a reproducible way and appropriate control measures can be selected.
Currently [when?] the clean up of historic contamination is controlled under a specific statutory scheme found in Part IIA of the Environmental Protection Act 1996 (Part IIA), as inserted by the Environment Act 1995, and other ‘rules’ found in regulations and statutory guidance. The Act came into force in England in April 2000.
A variable may be thought to alter the dependent or independent variables, but may not actually be the focus of the experiment. So that the variable will be kept constant or monitored to try to minimize its effect on the experiment. Such variables may be designated as either a "controlled variable", "control variable", or "fixed variable".
In case-control studies, matched variables most often are the age and sex. Drawback: Case-control studies are feasible only when it is easy to find controls, i.e. persons whose status vis-à-vis all known potential confounding factors is the same as that of the case's patient: Suppose a case-control study attempts to find the cause of a given ...
A scientific control is an experiment or observation designed to minimize the effects of variables other than the independent variable (i.e. confounding variables). [1] This increases the reliability of the results, often through a comparison between control measurements and the other measurements. Scientific controls are a part of the ...