Login

Reliability & Validity in Psychology: Definitions & Differences

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Statistical Analysis for Psychology: Descriptive & Inferential Statistics

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
 Replay
Your next lesson will play in 10 seconds
  • 0:57 Reliability
  • 1:29 Validity
  • 1:48 Construct Validity
  • 2:14 Internal Validity
  • 3:04 External Validity
Add to Add to Add to

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Login or Sign up

Timeline
Autoplay
Autoplay
Create an account to start this course today
Try it free for 5 days!
Create An Account

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Ellie Green

Ellie holds a B.A. with Honors in English from Stanford University. She is pursuing a Ph.D. in English Literature at Princeton University.

How do validity and reliability contribute to study design in psychology? In this lesson, you'll look at how experiments can fail reliability and validity requirements to get an idea of the challenges behind conducting significant psychological research.

Designing a psychological study isn't really that hard. If you've ever written a survey or taken a poll among your friends, you've conducted some crude psychological research. But designing a study that produces valuable and scientific results is really challenging. If you gave your friends a survey about their political leanings, they might be influenced by the way you phrased the questions or by knowing your own political opinions; your survey might not accurately measure what you think it does. Two key concepts for designing scientific psychological studies are reliability and validity. We'll look at some examples of both to better understand the importance of careful research design.

Do you have a friend or family member who will always help you out if you ask? You'd probably describe this friend as reliable. Reliability in psychological research isn't really that different - it means that your tools for measuring a given variable measure it accurately and consistently. If you use a rigid ruler to measure the length of your foot, you should always get the same length; this is a measurement that has test-retest reliability. But if instead you measure your foot by holding your fingers about an inch apart and then moving them down the length of your foot and counting as you go, you'd probably come up with different measurements each time. Your fingers are not a particularly reliable measurement tool for the length of your foot.

Important to designing and interpreting psychological research is the idea of validity. In general, validity refers to the legitimacy of the research and its conclusions: has the researcher actually produced results that support or refute the hypothesis? It can be easier to understand validity by looking at some of the ways that research can be not valid.

A study fails construct validity if what it chooses to measure doesn't actually correspond to the question it's asking. Let's say you were doing research that required you to know how intelligent your subjects were. To measure intelligence, you decide to administer a really difficult physics exam. If you did this, your experiment would lack construct validity because a score on a physics exam doesn't really measure intelligence; it just measures whether you've taken physics or not.

To unlock this lesson you must be a Study.com Member.
Create your account

Register for a free trial

Are you a student or a teacher?
I am a teacher
What is your educational goal?
 Back

Unlock Your Education

See for yourself why 10 million people use Study.com

Become a Study.com member and start learning now.
Become a Member  Back

Earning College Credit

Did you know… We have over 95 college courses that prepare you to earn credit by exam that is accepted by over 2,000 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it free for 5 days!
Create An Account
Support