3. Validity
When a questionnaire is described as a 'valid' research tool, it means that it measures what it is intended to measure. Four types of validity checking for questionnaires are important.
Click each of the buttons to learn what each of these concepts mean.
Face-validity involves reviewing the questionnaire to see whether its terms are related to the examined concept or whether there are some irrelevant parts of the questionnaire. This could be done simply by administering the questionnaire to a group of people and looking at the outcome. The participants in this checking step could be colleagues or friends, but preferably people who share relevant characteristics of the potential study subjects.
Content validity examines whether questionnaire items cover the examined construct/concept or whether some items are missing. This usually involves asking experts in the field of the study to evaluate the content of the questionnaire.
Criterion validity refers to how well questionnaire responses measure certain concepts or is an indicator or predictor of the outcome under examination. As an example, when you ask a question in your questionnaire about a patient’s subjective symptoms of high blood pressure and then compare this with the actual reading recorded in the file.
Construct validity determines whether the questionnaire accurately measures the concept of interest. This can be done through assessing the relation between the developed questionnaire and other tools used to examine the concept of interest.
As an example when a psychology researcher administers a new questionnaire for assessment of anxiety and another approved one for assessing the same concept and examines the correlation between the two questionnaires in assessing this construct. .