Final answer:
A scale with internal consistency is reliable in producing consistent results, but this does not ensure that it measures what it is intended to measure (validity), is valid, or is unbiased. Validity and reliability are distinct, yet interrelated, concepts in scale and test construction.
Step-by-step explanation:
If a scale is internally consistent, it means that it has high reliability. Reliability refers to the ability of the scale to produce consistent results under the same conditions. However, internal consistency does not guarantee that the scale is measuring what it intends to measure (validity), that it has high validity, or that it is unbiased. Validity encompasses several aspects, such as ecological validity, construct validity, and face validity, which assess whether the tool measures what it's intended to. It's critical to note that while any valid measure must also be reliable, a reliable measure is not necessarily valid.
In psychological assessments, there are validity scales like the Lie Scale to detect whether individuals may be presenting themselves in an unrealistically positive way, which affects the validity of the assessment results. Practitioners and researchers strive to use instruments that are both highly reliable and valid to obtain the most accurate and useful data.