【答案解析】According to Lado, there are two basic requirements that a test must fulfill: validity and reliability.
1) Validity is the degree to which a test measures what it is meant to measure. For example, if candidates are familiar with the topic, the validity of the test will be reduced. There are several kinds of validity: content validity, construct validity; empirical validity; and face validity.
2) Reliability can be defined as consistency. If a test produces the same or very similar results when given to the same candidates twice in succession or marked by different people, it is regarded as having high degree of reliability. There are two types of reliability: stability reliability and equivalence reliability.