U.S. flag

An official website of the United States government

The .gov means it's official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

  • Publications
  • Account settings
  • Browse Titles

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

Thompson M, Tiwari A, Fu R, et al. A Framework To Facilitate the Use of Systematic Reviews and Meta-Analyses in the Design of Primary Research Studies [Internet]. Rockville (MD): Agency for Healthcare Research and Quality (US); 2012 Jan.

Cover of A Framework To Facilitate the Use of Systematic Reviews and Meta-Analyses in the Design of Primary Research Studies

A Framework To Facilitate the Use of Systematic Reviews and Meta-Analyses in the Design of Primary Research Studies [Internet].

Appendix a assessing validity of systematic reviews, comprehensive literature search.

View in own window

Criteria Used to Select Articles for Inclusion Appropriate?

Included studies sufficiently valid for the type of question asked, were the results similar from study to study.

Other titles in these collections

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

Connect with NLM

National Library of Medicine 8600 Rockville Pike Bethesda, MD 20894

Web Policies FOIA HHS Vulnerability Disclosure

Help Accessibility Careers

statistics

Have a language expert improve your writing

Run a free plagiarism check in 10 minutes, generate accurate citations for free.

Reliability vs. Validity in Research | Difference, Types and Examples

Published on July 3, 2019 by Fiona Middleton . Revised on January 30, 2023.

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, and validity is about the accuracy of a measure.opt

It’s important to consider reliability and validity when you are creating your research design , planning your methods, and writing up your results, especially in quantitative research . Failing to do so can lead to several types of research bias and seriously affect your work.

Table of contents

Understanding reliability vs validity, how are reliability and validity assessed, how to ensure validity and reliability in your research, where to write about reliability and validity in a thesis.

Reliability and validity are closely related, but they mean different things. A measurement can be reliable without being valid. However, if a measurement is valid, it is usually also reliable.

What is 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.

What is 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.

If the thermometer shows different temperatures each time, even though you have carefully controlled conditions to ensure the sample’s temperature stays the same, the thermometer is probably malfunctioning, and therefore its measurements are not valid.

However, reliability on its own is not enough to ensure validity. Even if a test is reliable, it may not accurately reflect the real situation.

Validity is harder to assess than reliability, but it is even more important. To obtain useful results, the methods you use to collect data must be valid: the research must be measuring what it claims to measure. This ensures that your discussion of the data and the conclusions you draw are also valid.

Reliability can be estimated by comparing different versions of the same measurement. Validity is harder to assess, but it can be estimated by comparing the results to other relevant data or theory. Methods of estimating reliability and validity are usually split up into different types.

Types of reliability

Different types of reliability can be estimated through various statistical methods.

Types of validity

The validity of a measurement can be estimated based on three main types of evidence. Each type can be evaluated through expert judgement or statistical methods.

To assess the validity of a cause-and-effect relationship, you also need to consider internal validity (the design of the experiment ) and external validity (the generalizability of the results).

Receive feedback on language, structure, and formatting

Professional editors proofread and edit your paper by focusing on:

See an example

literature review and validity

The reliability and validity of your results depends on creating a strong research design , choosing appropriate methods and samples, and conducting the research carefully and consistently.

Ensuring validity

If you use scores or ratings to measure variations in something (such as psychological traits, levels of ability or physical properties), it’s important that your results reflect the real variations as accurately as possible. Validity should be considered in the very earliest stages of your research, when you decide how you will collect your data.

Ensure that your method and measurement technique are high quality and targeted to measure exactly what you want to know. They should be thoroughly researched and based on existing knowledge.

For example, to collect data on a personality trait, you could use a standardized questionnaire that is considered reliable and valid. If you develop your own questionnaire, it should be based on established theory or findings of previous studies, and the questions should be carefully and precisely worded.

To produce valid and generalizable results, clearly define the population you are researching (e.g., people from a specific age range, geographical location, or profession).  Ensure that you have enough participants and that they are representative of the population. Failing to do so can lead to sampling bias and selection bias .

Ensuring reliability

Reliability should be considered throughout the data collection process. When you use a tool or technique to collect data, it’s important that the results are precise, stable, and reproducible .

Plan your method carefully to make sure you carry out the same steps in the same way for each measurement. This is especially important if multiple researchers are involved.

For example, if you are conducting interviews or observations , clearly define how specific behaviors or responses will be counted, and make sure questions are phrased the same way each time. Failing to do so can lead to errors such as omitted variable bias or information bias .

When you collect your data, keep the circumstances as consistent as possible to reduce the influence of external factors that might create variation in the results.

For example, in an experimental setup, make sure all participants are given the same information and tested under the same conditions, preferably in a properly randomized setting. Failing to do so can lead to a placebo effect , Hawthorne effect , or other demand characteristics . If participants can guess the aims or objectives of a study, they may attempt to act in more socially desirable ways.

It’s appropriate to discuss reliability and validity in various sections of your thesis or dissertation or research paper . Showing that you have taken them into account in planning your research and interpreting the results makes your work more credible and trustworthy.

Cite this Scribbr article

If you want to cite this source, you can copy and paste the citation or click the “Cite this Scribbr article” button to automatically add the citation to our free Citation Generator.

Middleton, F. (2023, January 30). Reliability vs. Validity in Research | Difference, Types and Examples. Scribbr. Retrieved May 24, 2023, from https://www.scribbr.com/methodology/reliability-vs-validity/

Is this article helpful?

Fiona Middleton

Fiona Middleton

Other students also liked, what is quantitative research | definition, uses & methods, data collection | definition, methods & examples, what is your plagiarism score.

IMAGES

  1. PPT

    literature review and validity

  2. PPT

    literature review and validity

  3. (PDF) A review of the literature on the validity of mass casualty

    literature review and validity

  4. PPT

    literature review and validity

  5. (PDF) Investigating the Reliability and Validity of the Waterlow Risk

    literature review and validity

  6. (PDF) A Literature Review to Examine the Validity and Reliability of

    literature review and validity

VIDEO

  1. What is Literature Review?

  2. EVALUATING LITERATURE

  3. WHAT IS LITERATURE REVIEW? || PIKEZPEDIA

  4. Writing the Review of Related Literature

  5. Reviews of Related Literature : Research Topic

  6. Approaches to searching the literature

COMMENTS

  1. Assessing Validity of Systematic Reviews

    Assessing Validity of Systematic Reviews - A Framework To Facilitate the Use of Systematic Reviews and Meta-Analyses in the Design of Primary Research Studies - NCBI Bookshelf. An official website of the United States government. Here's how you know.

  2. (PDF) Validity and the review of literature

    Abstract and Figures. The purpose of the present paper is to link the review of literature to the concept of construct validity using Messick’s (1989, 1995) conception of validity as a unitary ...

  3. Critical Analysis of Reliability and Validity in Literature

    Critical Analysis of Reliability and Validity in Literature Reviews. Ellen Chetwynd, PhD, MPH, BSN, IBCLC, RLC https://orcid.org/0000-0001-5611-8778 View all authors and affiliations. Volume 38, Issue 3. https://doi.org/10.1177/08903344221100201. Contents.

  4. Guidance on Conducting a Systematic Literature Review

    In this article, through a systematic search on the methodology of literature review, we categorize a typology of literature reviews, discuss steps in conducting a systematic literature review, and provide suggestions on how to enhance rigor in literature reviews in planning education and research.