A positive control demonstrates an experiment is capable of producing a positive result. For example, let's say you are examining bacterial susceptibility to a drug. You might use a positive control to make sure the growth medium is capable of supporting any bacteria. You could culture bacteria known to carry the drug resistance marker, so they should be capable of surviving on a drug-treated medium. If these bacteria grow, you have a positive control that shows other drug-resistance bacteria should be capable of surviving the test.
Everyone within the University has some role in internal controls. An individual’s responsibility depends mainly on the level of involvement at the university. The Board of Trustees, President and senior administrators establish the presence of integrity, ethics, competence and a positive control environment. The department directors and managers are responsible for establishing and maintaining internal controls within their departments. Other department personnel are responsible for executing control policies and procedures established by department heads.
Calculated control A control whose source of data is an expression, rather than a field, is called a calculated control. You specify the value that you want to use as the source of data in the control by defining an expression . An expression can be a combination of operators (such as = and + ), control names, field names, functions that return a single value, and constant values. For example, the following expression calculates the price of an item with a 25 percent discount by multiplying the value in the Unit Price field by a constant value ().