Validity in research: a guide to measuring the right things

Validity in research is vital in conducting accurate studies or investigations that yield dependable results. Various tools and techniques are used to gather information in research. Accuracy is essential whether you're using measuring tools (like scales and rulers) or information-gathering tools (like surveys, questionnaires, and interviews).

Validity is necessary for all types of studies ranging from market validation of a business or product idea to the effectiveness of medical trials and procedures. So, how can you determine whether your research is valid? This guide can help you understand what validity is, the types of validity in research, and the factors that affect research validity.

In the most basic sense, validity is the quality of being based on truth or reason. Valid research strives to eliminate the effects of unrelated information and the circumstances under which evidence is collected. 

Validity in research is the ability to conduct an accurate study with the right tools and conditions to yield acceptable and reliable data that can be reproduced. Researchers rely on carefully calibrated tools for precise measurements. However, collecting accurate information can be more of a challenge.

Studies must be conducted in environments that don't sway the results to achieve and maintain validity. They can be compromised by asking the wrong questions or relying on limited data. 

Why is validity important in research?

Research is used to improve life for humans. Every product and discovery, from innovative medical breakthroughs to advanced new products, depends on accurate research to be dependable. Without it, the results couldn't be trusted, and products would likely fail. Businesses would lose money, and patients couldn't rely on medical treatments. 

While wasting money on a lousy product is a concern, lack of validity paints a much grimmer picture in the medical field or producing automobiles and airplanes, for example. Whether you're launching an exciting new product or conducting scientific research, validity can determine success and failure.

Reliability is the ability of a method to yield consistency. If the same result can be consistently achieved by using the same method to measure something, the measurement method is said to be reliable. For example, a thermometer that shows the same temperatures each time in a controlled environment is reliable.

While high reliability is a part of measuring validity, it's only part of the puzzle. If the reliable thermometer hasn't been properly calibrated and reliably measures temperatures two degrees too high, it doesn't provide a valid (accurate) measure of temperature. 

Similarly, if a researcher uses a thermometer to measure weight, the results won't be accurate because it's the wrong tool for the job. 

While measuring reliability is a part of measuring validity, there are distinct ways to assess both measurements for accuracy. 

How is reliability measured?

These measures of consistency and stability help assess reliability, including:

• Consistency and stability of the same measure when repeated multiple times and conditions

• Consistency and stability of the measure across different test subjects

• Consistency and stability of results from different parts of a test designed to measure the same thing

How is validity measured?

Since validity refers to how accurately a method measures what it is intended to measure, it can be difficult to assess the accuracy. Validity can be estimated by comparing research results to other relevant data or theories.

• The adherence of a measure to existing knowledge of how the concept is measured

• The ability to cover all aspects of the concept being measured

• The relation of the result in comparison with other valid measures of the same concept

Research validity is broadly gathered into two groups: internal and external. Yet, this grouping doesn't clearly define the different types of validity. Research validity can be divided into seven distinct groups.

• Face validity: A test that appears valid simply because of the appropriateness or relativity of the testing method, included information, or tools used.

• Content validity: The determination that the measure used in research covers the full domain of the content.

• Construct validity: The assessment of the suitability of the measurement tool to measure the activity being studied.

• Internal validity: The assessment of how your research environment affects measurement results. This is where other factors can’t explain the extent of an observed cause-and-effect response.

• External validity: The extent to which the study will be accurate beyond the sample and the level to which it can be generalized in other settings, populations, and measures.

• Statistical conclusion validity: The determination of whether a relationship exists between procedures and outcomes (appropriate sampling and measuring procedures along with appropriate statistical tests).

• Criterion-related validity: A measurement of the quality of your testing methods against a criterion measure (like a “gold standard” test) that is measured at the same time.

Like different types of research and the various ways to measure validity, examples of validity can vary widely. These include:

• A questionnaire may be considered valid because each question addresses specific and relevant aspects of the study subject.

• In a brand assessment study, researchers can use comparison testing to verify the results of an initial study. For example, the results from a focus group response about brand perception are considered more valid when the results match that of a questionnaire answered by current and potential customers.

• A test to measure a class of students' understanding of the English language contains reading, writing, listening, and speaking components to cover the full scope of how language is used.

Certain factors can affect research validity in both positive and negative ways. By understanding the factors that improve validity and those that threaten it, you can enhance the validity of your study. These include:

• Random selection of participants vs. the selection of participants that are representative of your study criteria

• Blinding with interventions the participants are unaware of (like the use of placebos)

• Manipulating the experiment by inserting a variable that will change the results

• Randomly assigning participants to treatment and control groups to avoid bias

• Following specific procedures during the study to avoid unintended effects

• Conducting a study in the field instead of a laboratory for more accurate results

• Replicating the study with different factors or settings to compare results

• Using statistical methods to adjust for inconclusive data

What are the common validity threats in research, and how can their effects be minimized or nullified?

Research validity can be difficult to achieve because of internal and external threats that produce inaccurate results. These factors can jeopardize validity.

• History: Events that occur between an early and later measurement

• Maturation: The passage of time in a study can include data on actions that would have naturally occurred outside of the settings of the study

• Repeated testing: The outcome of repeated tests can change the outcome of followed tests

• Selection of subjects: Unconscious bias which can result in the selection of uniform comparison groups

• Statistical regression: Choosing subjects based on extremes doesn't yield an accurate outcome for the majority of individuals

• Attrition: When the sample group is diminished significantly during the course of the study

• Maturation: When subjects mature during the study, and natural maturation is awarded to the effects of the study

While some validity threats can be minimized or wholly nullified, removing all threats from a study is impossible. For example, random selection can remove unconscious bias and statistical regression. 

Researchers can even hope to avoid attrition by using smaller study groups. Yet, smaller study groups could potentially affect the research in other ways. The best practice for researchers to prevent validity threats is through careful environmental planning and t reliable data-gathering methods. 

Researchers should be mindful of the importance of validity in the early planning stages of any study to avoid inaccurate results. Researchers must take the time to consider tools and methods as well as how the testing environment matches closely with the natural environment in which results will be used.

The following steps can be used to ensure validity in research:

• Choose appropriate methods of measurement

• Use appropriate sampling to choose test subjects

• Create an accurate testing environment

How do you maintain validity in research?

Accurate research is usually conducted over a period of time with different test subjects. To maintain validity across an entire study, you must take specific steps to ensure that gathered data has the same levels of accuracy. 

Consistency is crucial for maintaining validity in research. When researchers apply methods consistently and standardize the circumstances under which data is collected, validity can be maintained across the entire study.

Is there a need for validation of the research instrument before its implementation?

An essential part of validity is choosing the right research instrument or method for accurate results. Consider the thermometer that is reliable but still produces inaccurate results. You're unlikely to achieve research validity without activities like calibration, content, and construct validity.

Without validity, research can't provide the accuracy necessary to deliver a useful study. By getting a clear understanding of validity in research, you can take steps to improve your research skills and achieve more accurate results.