When we talk about quality research, we talk about the reliability and validity of the research. The research is considered valid when the measurement method measures what it claims to measure. There are four types of validity: face validity, criterion-related validity, construct validity, and content validity. This article discusses the content validity.
What is content validity?
When a test or assessment instrument evaluates all the characteristics of a construct or the behavior of a topic, what it claims to measure is called content validity. The content’s validity may be high or low. High level shows that all the topics are covered by the test for the target audience. On the other hand, a low level indicates that the test does not cover all the topics of the subject matter for the audience.
Measurement of content validity
The measurement process involves the assessment of the individual questions on a test. It asks the experts to check whether each item or question covers the characteristics that the test is designed to cover. The goals of the construct are compared with the test in this process. It is made sure that each item contributes to this process. The common steps and approaches used for measuring the validity of the content are presented in the following paragraphs.
Defining the content domain
The measurement starts with the definition of the content domain or construct that the instrument intends to measure. This process involves the identification of the main parts and dimensions of the concerned construct.
Item generation
The next step is the generation of a pool of questions or items that could possibly be included in the research instrument or test. The test items should represent the relevant aspects of the construct and should be based on the definite content domain.
Review by experts
In order to review the items or questions regarding the specific construct, a panel of experts with expertise in that particular content area is gathered. They are presented with the already-collected pool of potential items. Furthermore, they are asked to give feedback on the relevance, representativeness, clarity, and comprehensiveness of each item of the test or measurement. These experts can provide comments and give suggestions for modifications to the test items.
Content validity index (CVI):
In this step, the index for each item is calculated. CVI is a numerical representation of the opinion of the experts. It indicates the proportion of experts who agree that a question or item is representative of the content domain. It is calculated by the number of experts who rate an item divided by the total number of experts.
Selection of items and revision:
On the basis of CVI scores and the feedback of the experts, those items are identified as having high content validity. On the other hand, items with low CVI are either removed or revised. Similarly, considering the comments and suggestions of experts, the items are revised. The purpose is to improve the wording, clarity, and coverage of the items.
Pilot testing:
In this step, the revised research instrument is administered to a small group of participants for the collection of the required data. The data is then analyzed to assess the relevancy and appropriateness of the items in the test. Furthermore, response patterns, means of the items, and their variability indicate to what extent the included items effectively measure the content domain.
Ongoing Evaluation:
The process of establishing such validity is an ongoing process that continuously reviews and updates the research instrument on the basis of feedback from experts. The instrument is regularly assessed and validated to ensure its continued relevance and effectiveness.
The importance of content validity
It helps in answering questions such as “Does the measurement tool include all the aspects of the construct that the researcher wants to measure?” If yes, then this measurement tool has high content validity. A higher value indicates that the construct is accurately measured.
If the measurement tool does not include all parts of the construct, then the validity of the measurement tool is threatened, and the question is raised about the results of the research.
When is content validity used?
The content’s validity is used in the following situations:
Educational assessment:
From the perspective of educational assessment, validity is the extent to which the test or measurement instrument precisely measures what it claims to measure.
The educational assessment has profound impacts on the academics and futures of the students. For example, the students can face failure, and their future can be at stake if a test poorly measures their abilities. The validity assessment of the students is affected by numerous factors, such as
Directions for the assessment:
If the directions to the respondents in the test are unclear, the validity of the test or tool will be reduced.
Vocabulary:
The validity of the tool is affected by the vocabulary of the respondents. If the vocabulary is poor, then understanding of the items will be difficult and ultimately badly affect the validity of the instrument.
Construction of the test items:
If the items are poorly constructed and they convey different meanings to various respondents, the validity is badly affected.
Items’ difficulty level:
If the items in the test are too easy or too difficult, then they respondents would not be able respond to accurately due to inability to discriminate and as result the validity of the test would be lowered.
Extraneous variables’ affect:
The validity of the instrument is influenced due to the influence of extraneous variables.
Factor of time limit:
Unsuitable time limit given in the completion of the test will lead to affect the validity of the test. Similarly, in a power test, inappropriate time limit will also lower the validity of the test.
Interviews:
The content validity of the interview can be badly affected if the interviewers ask different questions on specific topics from different candidates. This will make difficult to compare the candidates. Secondly if the interviewers show personal biasedness in making judgment about the candidates, it will also lower the validity. Finally the format of the interview may be defective.
Questionnaires:
The type of questions asked also affect the content validity of a test. So, open-ended questions are less biased as compared to closed-ended questions. Therefore, it is important that in the preparation of questionnaire, leading questions should be avoided. It is because they may influence the answers of the respondents. It is recommended therefore, that concise and clear questions should be asked to avoid confusion.
Content validity examples
Some of the examples of content validity from different contexts have been discussed here.
Content validity example 1:
If the researcher wants to assess the health needs. Then he should include items related to all aspects of health i-e Physical, mental, social and emotional in order to have high content validity of the questionnaire.
Content validity example 2:
If an interviewer wants to prepare interview for recruiting people in his company, then he should prepare all the items related to his job requirement. If he does so, the content validity of his interview question would be high.
Content validity example 3:
Take the situation in which the researchers want to develop a new assessment tool for assessing the depression in the patients. For establishing the content validity, they would make sure that all the aspects of depressive symptoms are covered which they intend to measure. For this purpose, they will consult the relevant literature, theories, along with opinion of the experts.
Content validity example 4:
Take the example of the situation where the teachers develop a statistics test for students. In this case the content validity would ensure that the items of the test cover all the aspects of statistics test.
Content validity example 5:
If a researcher of subject of education wants to assess the leadership styles of the heads of the institutions, then the researcher would include all the items related to different leadership styles.
Advantages of content validity:
This heading discusses the advantages of content validity.
- Relevant items regarding the construct are included in the test.
- It is made sure that the measurement tool covers all the aspects of the construct being measured.
- Since the process of development of the tool involves the opinions of the experts as well, its credibility and accuracy is enhanced.
- The face validity of the tool is also enhanced if the content validity is high.
- Since a valid content accurately represents the construct, it becomes easier to interpret the obtained results.
Disadvantages of content validity:
Although content validity has advantages, it also has some limitations.
- Since subjectivity is involved in the interpretations of different experts, therefore, the overall content validity of the tool can be affected in the form of the introduction of biasedness.
- The overall validity cannot be assessment by the content validity; therefore, it has limited scope.
- Content validity is not assessed through statistical analysis and mere expert opinion is used, therefore, it can limit the objectivity and generalizability of the content validity.
- Content validity is used in the assessment of observable constructs. While it becomes difficult to assess the complex constructs, therefore, it may become a limitation of the content validity.
- Content validity alone cannot establish the predictive validity. Rather additional studies and evidences are necessary for this purpose.