Validity and Reliability

Reliability and Validity

Reliability and validity are concepts used to evaluate the quality of research. They indicate how well a method, technique or test measures something. 

Reliability is about the consistency of a measure.

Validity is about the accuracy of a measure. 

Reliability

Reliability refers to how consistently a method measures something. If the same result can be consistently achieved by using the same methods under the same circumstances, the measurement is considered reliable.

Example: Measuring humidity in forest vs open field

Reliable if repeated readings over short intervals are stable (e.g., 72%, 73%, 72%). 

Validity

Validity refers to how accurately a method measures what it is intended to measure. If research has high validity, that means it produces results that correspond to real properties, characteristics, and variations in the physical or social world. High reliability is one indicator that a measurement is valid. If a method is not reliable, it probably isn’t valid. 

Example: 

Measuring humidity in forest vs open field

Valid if placed where it measures air humidity, not affected by water splash or condensation on sensor.