Chlorine dioxide (ClO 2) is a gas that can be used for water disinfection. To date, only uncut and unpeeled produce can be contacted with ClO 2. Chlorine dioxide has been given a USDA 3-D approval for washing fruits and vegetables to be used as ingredients of meat and poultry products.he chemicals that make up chlorine dioxide can also be easily identified by the user. Sodium chlorite is a white crystalline powder. One of its physical characteristics is its ability to absorb moisture. The other component of chlorine dioxide, hydrochloric acid, is a colorless liquid.
The validity of a test refers to whether the test measures what it is supposed to measure. The three most common types of validity are face validity, empirical validity, and construct validity. We consider these types of validity below.
Construct validity. Construct validity is the degree to which a test measures what it claims, or purports, to be measuring.. In the classical model of test validity, construct validity is one of three main types of validity evidence, alongside content validity and criterion validity. Modern validity theory defines construct validity as the overarching concern of validity research, subsuming all other types of validity evidence.