​Which of the following is correct?​

Correct option is C

Reliability and validity are intrinsically linked concepts in the field of research methodology. Reliability refers to the consistency or repeatability of a measure, meaning that the results are stable over time and under consistent conditions. Validity, on the other hand, indicates whether the research instrument truly measures what it intends to measure.

An instrument can be reliable without being valid. For instance, a weighing scale that consistently shows the same incorrect weight is reliable but not valid. However, an instrument cannot be valid unless it is reliable. That is because inconsistent results undermine the credibility of any inferences drawn from the data. Therefore, for an instrument to be considered robust in research, it must be both reliable and valid.

Face validity, which is the focus of option (d), is the most superficial form of validity. It assesses whether the test appears to measure what it claims to measure, often based on subjective judgment. It lacks the statistical rigor found in other types of validity, such as content, construct, or criterion validity. Hence, asserting that face validity is the strongest method is incorrect.

Option (a) and (b) incorrectly state that validity does not concern accuracy or errors, which is misleading. Validity fundamentally assesses the accuracy and soundness of the measurement, ensuring that systematic and random errors are minimized.

Information Booster:

Reliability ensures consistent results under consistent conditions.

Validity evaluates if the instrument measures what it is intended to.

Types of validity include content, construct, criterion, internal, and external validity.

Face validity is the most superficial form and lacks empirical testing.

A valid test must also be reliable, but a reliable test may not necessarily be valid.

Systematic errors affect validity, while random errors affect reliability.

Triangulation methods are often used to improve both validity and reliability in qualitative research.

Additional Knowledge:

(a) Validity does not focus on the accuracy of instrument's measurement – This is incorrect because accuracy is central to validity. Valid instruments produce results that reflect the true measure.

(b) Validity does not check the systematic and random errors in the measurement process – Incorrect. Validity concerns include checking for both systematic and random errors that could affect measurement.

(c) Reliability and validity are related to each other – Correct. The interrelationship is foundational in research; without reliability, the validity of a measure is compromised.

(d) Face validity is probably the strongest way to find out the validity of the measurement for a research – Incorrect. Face validity is considered the weakest form due to its subjective nature.