1. ESTABLISHING RELIABILITY AND VALIDITY OF RESEARCH TOOLS Prof. HCL Rawat Principal UCON,BFUHS Faridkot

2. TOOL/INSTRUMENT Refers to the device used to collect data. Such as questionnaire, interview etc.

3. Quality of tool An ideal data collection procedure is one that captures a construct in such a way that is relevant/valid, credible, accurate, truthful and sensitive.

4. Assessment tools It includes four types of tests / measures: 1.Reliability 2.Validity 3.Sensitivity and specificity 4.Efficiency Reliability and validity are important tests to measure quantitative data

5. INTRODUCTION Reliability The consistency with which an instrument measures a given variables VALIDITY The extent to which the instrument measures what it is intended to measure “To be a measuring instrument (test) must be both valid and reliable”

6. RELIABILITY The quality and adequacy of quantities data can only be assessed by establishing the reliability of an instrument. Reliability refers to the consistency of a measure of instrument If a research instrument yields similar or close to similar results on repeated administration of instrument, it is considered as highly reliable research instrument. Various statistical procedures need to be performed to determine the reliability of a research tool Can be performed on the data collected for validity

7. Definition of reliability Reliability is the degree of consistency and accuracy with which an instrument measures the attribute for which it is designed to measure OR The ability of an instrument to create reproducible results

8. Types of reliability Three types of reliability: Stability reliability Equivalence reliability Internal consistency reliability

9. Stability reliability Refers to consistency over time. Also known as test- retest reliability. The test is administered twice at two different points in time. Test – retest reliability is best used for things that are stable over time. It is used for questionnaire, observation checklist, observation rating scales and physiological measurement tools

10. Equivalence reliability It refers to degree to which two different forms of an instrument obtain the same result. Or Two or more observers using a single instrument obtain the same result So reliability are terms used when two forms of same instrument are compared

11. Contd: In this two presumably parallel instruments are administered to an individual at same time. This is also known as interater or interobserver reliability. Calculated by using equation: r = No. of agreements No. of disagreements

12. Internal consistency reliability Also called homogeneity It refers to all the items of an instrument measure a same variables. This type of reliability is appropriate only when instrument is examining one concept

13. Contd: The most primitive approach of assessing the internal consistency is the split half technique. Split half includes that divide item of research instrument in two equal parts through grouping. Administer two parts of the tool simultaneously, score them independently and compute the correlation coefficient

14. Validity Validity of an instrument refers to the degree to which an instrument measures what it is suppose to be measured. Validity also asks that if an instrument measures what it is suppose, how “accurate” or “true” the measurement. Validity is the appropriateness, completeness and usefulness of an attribute measuring research instrument

15. Definition Validity refers to an instrument or test actually testing what it suppose to be testing. Validity refers to the degree to which an instrument measures what it suppose to measure Polit & Hungler Treece & Trecee

16. Categories of validity External validity Is the extent to which the results of a study can be generalized from a sample to a population Content validity Refers to the appropriateness of the content of an instrument

17. Types of validity Criterion – related /Face validity Content validity Concurrent validity Construct validity

18. Criterion-related / Face validity Involves an over all look of an instrument To measure appropriateness of a particular attribute or phenomena To measure or correlates to other criterion rather than to ascertain how well the tool measure the particular phenomena

19. Content validity Concerned with the scope of coverage of the content area to be measured. Applied in tests of knowledge measurement Mostly used in measuring complex psychological tests of a person. Used in case of a expert judgment about content in research to measure in particular phenomena

20. Criterion validity Type of validity is a relationship between measurements of the instrument with some external criteria. Later a correlation coefficient calculated to assess criterion validity The problem with criterion related validity is finding a reliable and valid external criterion

21. Construct Validity It refers to the degree of to which the measures the construct it is supposed to measure. Key criterion for assessing the quality of a study. Construct validity has most often been addressed in terms of measurements issues of study. Involves the measurement of variable that is not directly observable

22. Factors affecting while choosing tools/instruments Ease of use: Do you know how to use it? Access: Do you have access to the instrument? Appropriateness: Is it the best tool for what you are measuring? Accuracy: How precise do your measurements have to be? Cost: How expensive it is to be use or interpret the results?

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