---
url: "https://questionstar.com/principles-of-survey-research/chapter-2/slide-075.html"
title: "Relationship between Reliability and Validity"
type: "lehrbuch-slide"
chapter: 2
chapterTitle: "Survey: Measurement and Scaling"
slide: 75
---

# Relationship between Reliability and Validity

*Relationship*

![Hits tightly grouped, but off-center](/principles-of-survey-research/media/target1.png)

Reliable

but not valid

![Hits loosely scattered around the center](/principles-of-survey-research/media/target2.png)

Low reliability

low validity

![Hits widely scattered and off-center](/principles-of-survey-research/media/target3.png)

Not reliable

not valid

![Hits tightly grouped at the center](/principles-of-survey-research/media/target4.png)

Reliable and valid

the goal

✓ Validity implies reliability.XO = XT ⟹ XS = 0, XR = 0

✗ Non-reliability implies non-validity.XR ≠ 0 ⟹ XO = XT + XR ≠ XT

✗ Reliability does not imply validity.XR = 0, XS ≠ 0 ⟹ XO = XT + XS ≠ XT

Reliability is a **necessary** , but **not sufficient** condition for validity.

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*Slide 75 of 274 · Chapter 2: Survey: Measurement and Scaling · Principles of Survey Research · Dr. Paul Marx*