Types of validity across all methods of investigation: face validity,…

The idea

Validity concerns the accuracy of a measure across all methods of investigation—whether it genuinely measures what it claims to. Face validity assesses if a test appears to measure the target variable 'on the face of it'. Concurrent validity compares results from a new test with an established test; a strong positive correlation (+0.80) indicates high validity. Ecological validity refers to whether findings generalise to real-world settings, while temporal validity assesses if findings hold true across different eras. Validity is measured via correlation or expert review. It can be improved by using control groups, standardising procedures to reduce investigator effects, ensuring anonymity to minimise social desirability, or using covert observations.

What earns the marks

• Define validity as the extent to which an observed effect is genuine and measures what it intends to measure.
• Distinguish between ecological validity (generalising to other settings) and temporal validity (generalising to other times).
• Explain that concurrent validity is measured by correlating scores on a new test with an existing, recognised test, requiring a coefficient of +0.80 or higher.
• Describe face validity as an intuitive check, often by an expert, to see if the instrument looks like it measures the intended construct.
• Identify ways to improve validity, such as incorporating a control group, using double-blind procedures, or ensuring participant anonymity.

Common mistakes and how to put them right

• Equating ecological validity simply with the realism of the environment.

  Put it right: Ecological validity specifically refers to whether the findings can be generalised beyond the research setting to everyday life.

• Confusing concurrent validity with reliability.

  Put it right: Concurrent validity compares a new test to a different, established test, whereas reliability compares the same test against itself.

• Assuming face validity is a robust statistical measure.

  Put it right: Face validity is a subjective, superficial assessment and does not statistically prove validity.

Exam tips

• When evaluating a study's ecological validity, focus on the nature of the task (mundane realism) as well as the setting.
• If asked how to assess validity, explicitly describe the process of concurrent validity, including the need for a strong positive correlation.
• To suggest improvements for validity in questionnaires, recommend incorporating a lie scale to control for social desirability bias.