In evaluating a measurement instrument for a study, which quality must be established first before it is used to draw conclusions?

In evaluating a measurement instrument for a study, which quality must be established first before it is used to draw conclusions?

• A. Reliability
• B. Validity
• C. Generalizability
• D. Feasibility

Answer: (A)

Reliability is the essential prerequisite. It focuses on consistency: if you repeated the measurement under the same conditions, you should obtain similar results. When a tool yields unpredictable or fluctuating scores, you’re unsure whether any observed differences reflect real effects or just random measurement error, so you can’t draw trustworthy conclusions. Once reliability is established, you can then assess validity—whether the instrument actually measures what it intends to measure. Generalizability and feasibility matter for applying the instrument, but they don’t guarantee that the data you’re drawing conclusions from are trustworthy.

Reliability is the essential prerequisite. It focuses on consistency: if you repeated the measurement under the same conditions, you should obtain similar results. When a tool yields unpredictable or fluctuating scores, you’re unsure whether any observed differences reflect real effects or just random measurement error, so you can’t draw trustworthy conclusions. Once reliability is established, you can then assess validity—whether the instrument actually measures what it intends to measure. Generalizability and feasibility matter for applying the instrument, but they don’t guarantee that the data you’re drawing conclusions from are trustworthy.