Give a brief description of reliability and validity of an assessment instrument. Explain how an assessment instrument can be reliable but not be valid. Then, explain why an assessment instrument that is not reliable can never be deemed valid. Provide an example to illustrate your point.
On the Likert Scale
What is the Likert Scale? It is a psychometric testing device that is the most popular form of measurement in survey research. What the Likert does is present a questionnaire with each question provided a corresponding set of answers whereby the respondent has a choice of items along a range. The idea is that each point indicated in the range is also in accordance with the choice items as it is a manner of rating according to views and positions - a psychometric device that quantified ideas, opinions and choices. In a way, a Likert scale allows for simplification of often complex ideas and opinions when it comes to choices as well as opinion constructs that are often abstract but indicative of human qualities, values and virtues. For example, a survey pertaining to measure self-perception can have the following item listed - "I feel beautiful inside and out," whereby the choices in terms of answers are - ...
The reliability and validity of an assessment instruments are examined. Why an assessment instruments that is not reliable can never be deemed valid is determined.