Dr. Liu developed a new measure of fear of crime. His conceptual definition was: the degree of emotional, behavioral, or mental response to a real or imagined theft of property or attack on one’s person or family members. He then developed one question for a survey to measure his concept: "Do you lock your car doors when you run into a convenience store to pay for your gas?" What is the MAJOR problem with his measure?

It refers to the degree to which an assessment instrument is relevant and is representative of, the targeted construct it is designated for. It played a role in the development of a new instrument by assessing the degree to which the instrument measures the targeted construct. This enables the instrument to be used to make meaningful and appropriate inferences or decisions from the score given the purpose. All instruments can affects the score obtained. The interpretation made should be subject validation.

There are key aspects of content validation:

Domain definition

Domain representation

Domain relevance