LESSON 10 STABLISHING VALIDITY AND REALBILITY OF RESEARCH INSTRUMENT- DAGAMI.pptx

Reliability and Validity
Quantitative Methodology
Reliability and validity are important aspects of selecting a survey instrument. Reliability refers to the extent that the instrument yields the same results over multiple trials. Validity refers to how well the instrument measures what you intend it to measure. In research, there are three ways to approach validity and they include content validity, construct validity, and criterion-related validity.

Content validity evaluates how well the items on the scale represent or measure the information you intend to assess. Do the questions you ask represent all the possible questions you could ask?


Construct validity measures what the calculated scores represent and whether you can generalize them. Construct validity uses statistical analyses, such as correlations, to verify the relevance of the questions. You can correlate questions from an existing, reliable instrument with questions from the instrument under examination to determine if construct validity is present. High correlation between the scores indicates convergent validity. If you establish convergent validity, you support construct validity.

Criterion-related validity refers to how well the instrument’s scores predict a known outcome that you expect them to predict. You use statistical analyses, such as correlations, to determine if criterion-related validity exists. You should correlate scores from the instrument with an item they knew to predict. If a correlation of > .60 exists, criterion related validity exists as well.

You can assess reliability using the test-retest method, alternative form method, internal consistency method, split-halves method, and inter-rater reliability.

Test-retest is a method that administers the same instrument to the same sample at two different points in time, perhaps one year intervals. If you find that the scores at both time periods correlate highly (> .60), you can consider them reliable. The alternative form method requires two different instruments consisting of similar content. You must have the same sample take both instruments, and then you correlate the scores from both instruments. If you find high correlations, you can consider the instrument reliable. Internal consistency uses one instrument administered only once.

You use the coefficient alpha (or Cronbach’s alpha) to assess the internal consistency of the items. If the alpha value is .70 or higher, you can consider the instrument reliable. The split-halves method also requires one test administered once. The number of items in the scale are divided into halves and a correlation is taken to estimate the reliability of each half of the test. To estimate the reliability of the entire survey, the Spearman-Brown correction must be applied. Inter-rater reliability involves comparing the observations of two or more individuals and assessing the agreement of the observations. Kappa values can be calculated in this instance. Question

1. Stablishing Validity and Reliability of Research Instrument 1

2. ` Topic Learning Outcomes Describe the concept of validity Explain the different types of validity Describe the concept of reliability Explain factors affecting the reliability of a research instrument Illustrate methods of determining the reliability of an instrument Differentiate validity and reliability 2

3. ` Topic Learning Outcomes Describe the concept of validity Explain the different types of validity Describe the concept of reliability Explain factors affecting the reliability of a research instrument Illustrate methods of determining the reliability of an instrument Differentiate validity and reliability 2

4. ` Topic Learning Outcomes Describe the concept of validity Explain the different types of validity Describe the concept of reliability Explain factors affecting the reliability of a research instrument Illustrate methods of determining the reliability of an instrument Differentiate validity and reliability 2

5. ` Topic Learning Outcomes Describe the concept of validity Explain the different types of validity Describe the concept of reliability Explain factors affecting the reliability of a research instrument Illustrate methods of determining the reliability of an instrument Differentiate validity and reliability 2

6. 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. 3

7. Questionnaire is one of the most widely used tools to collect data especially in social science research. The main objective of questionnaire in research is to obtain relevant information in most reliable and valid manner. 4

8. 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. https://www.scribbr.com/methodology/reliability-vs-validity/ 5

9. What is Validity ? 6

10. What is Validity ? 6

11. What is Validity ? 6

12. What is Validity ? 6

13. 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. 7

14. Validity explains how well the collected data covers the actual area of investigation. Validity basically means “measure what is intended to be measured” 8

15. Types Of Validity (Quantitative Research) 9

16. Face and Content Validity Concurrent and Predictive Validity Construct Validity Types Of Validity 10

17. Face Validity : It's how a test looks like it measures what it's supposed to measure, based on a surface-level examination. Content Validity : It's about whether a test actually measures the content or material it's supposed to measure, based on expert judgment and analysis of the test items. Face and Content Validity 11

18. Face Validity : It's how a test looks like it measures what it's supposed to measure, based on a surface-level examination. Content Validity : It's about whether a test actually measures the content or material it's supposed to measure, based on expert judgment and analysis of the test items. Face and Content Validity 11

19. Face Validity : It's how a test looks like it measures what it's supposed to measure, based on a surface-level examination. Content Validity : It's about whether a test actually measures the content or material it's supposed to measure, based on expert judgment and analysis of the test items. Face and Content Validity 11

20. Face Validity : It's how a test looks like it measures what it's supposed to measure, based on a surface-level examination. Content Validity : It's about whether a test actually measures the content or material it's supposed to measure, based on expert judgment and analysis of the test items. Face and Content Validity 11

21. II. Concurrent and Predictive Validity Predictive validity is judged by the degree to which an instrument can forecast an outcome. Concurrent validity is judged by how well an instrument compares with a second assessment concurrently done. 12

22. III. Construct Validity Is a more sophisticated technique for establishing the validity of an instrument - based upon statistical procedures. Determined by ascertaining the contribution of each construct to the total variance observed in a phenomenon. The greater variance attributable to the constructs, the higher the validity of the instrument 13

23. What is Reliability? 14

24. 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. 15

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29. The Wording of Questions A slight ambiguity in the wording of questions or statements can affect the reliability of a research instrument as respondents may interpret the questions differently sometimes resulting in different responses. The Physical Setting Any change in the physical setting at the time of the repeat interview may affect the responses given by a respondent, which may affect reliability. 17

30. The Respondent’s Mood A change in a respondent's mood when responding to questions or writing answers in a questionnaire can change and may affect the reliability of that instrument. The Interviewer’s Mood As the mood of a respondent could change from one interview to another so could the mood, motivation and interaction of the interviewer, which could affect the responses given by respondents thereby affecting the reliability of the research instrument. 18

31. The Regression Affect of an Instrument When a research instrument is used to measure attitudes towards an issue , some respondents, after having expressed their opinion, may feel that they have been either too negative or too positive towards the issue. The second time they may express their opinion differently, thereby affecting reliability. 19

32. The Nature of Interactions In an interview situation, the interaction between the interviewer and the interviewee can affect responses significantly. During the repeat interview the responses given may be different due to a change in interaction , which could affect reliability. 20

33. The Nature of Interactions In an interview situation, the interaction between the interviewer and the interviewee can affect responses significantly. During the repeat interview the responses given may be different due to a change in interaction , which could affect reliability. 20

34. The Nature of Interactions In an interview situation, the interaction between the interviewer and the interviewee can affect responses significantly. During the repeat interview the responses given may be different due to a change in interaction , which could affect reliability. 20

35. The Nature of Interactions In an interview situation, the interaction between the interviewer and the interviewee can affect responses significantly. During the repeat interview the responses given may be different due to a change in interaction , which could affect reliability. 20

36. Methods of D etermining the R eliability of an R esearch I nstrument ( Q uantitative R esearch ) 21

37. External C onsistency P rocedures Test / R etest Commonly used method for establishing the reliability of a research tool . In the test/retest an instrument is administered once . The greater the value of the ratio, the higher the reliability of an instrument As an equation : Test score / retest = 1 Test score - retest= 0 22

38. Parallel Forms of The Same Test Can construct two instruments that are intended to measure the same phenomenon Two instrument administered to two similar populations. The result obtained from one test are compared with those obtained from the other. If similar, assumed that the instrument is reliable. 23

39. Internal C onsistency P rocedures The S plit-half T echnique Is designed to correlate half of the items with other half appropriate for instruments that are designed to measure attitudes towards an issue The question are divided in half in such a way that any two questions intended to measure the same aspects fall into different halves The Scores obtained by administering the two halves are correlated Reliability is calculated by using the product moment correlation. Because the product moment correlation is calculated on the bases of only half the instrument, it needs to be corrected to assess reliability for the whole, known as stepped up reliability (called the Spearman-Brown formula) 24

40. Understanding R eliability vs V alidity 25

41. Understanding R eliability vs V alidity 25

42. Understanding R eliability vs V alidity 25

43. Understanding R eliability vs V alidity 25

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49. Reliability vs V alidity   Reliability Validity What does it tell you? The extent to which the results can be reproduced when the research is repeated under the same conditions. The extent to which the results really measure what they are supposed to measure. How is it assessed? By checking the consistency of results across time, across different observers, and across parts of the test itself. By checking how well the results correspond to established theories and other measures of the same concept. How do they relate? A reliable measurement is not always valid: the results might be reproducible but they’re not necessarily correct. A valid measurement is generally reliable: if a test produces accurate results, they should be reproducible. 27

50. 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. 2 8

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