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VALIDITY vs. RELIABILITY by: Ivan Prasetya

VALIDITY vs. RELIABILITY by: Ivan Prasetya. Because of measuring the social phenomena is not easy like measuring the physical symptom and because there are a lot of MEASUREMENT ERROR in measuring social phenomena, so we should do VALIDITY & RELIABILITY TESTING. VALIDITY vs. RELIABILITY.

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VALIDITY vs. RELIABILITY by: Ivan Prasetya

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  1. VALIDITY vs. RELIABILITYby: Ivan Prasetya

  2. Because of measuring the social phenomena is not easy like measuring the physical symptom and because there are a lot of MEASUREMENT ERROR in measuring social phenomena, so we should do VALIDITY & RELIABILITY TESTING.

  3. VALIDITY vs. RELIABILITY • Measurement VALIDITY: How well an empirical indicator and the conceptual definition of the construct that the indicator is suppose to measure ‘fit’ together. • Measurement RELIABILITY: The independability or consistency of the measure of a variable.

  4. Different tools are usedfor measuring different things A tape measure is used to measure length or distance. A thermometer is used to measure temperature. A stopwatch is used to measure time.

  5. If we want to measure weight/mass,we can use these tools: Digital scale have the highest VALIDITY. (1 litre = 1 kg)

  6. However, even though a digital scale has the highest validity, but if the subject is not cooperative, the test result will not be accurate: If you keep jumping around while measuring your weight, you won't get an accurate result of your body weight. And if you carry extra loads while stepping on a digital scale, you won't get an accurate result of your body weight either. High Validity, Low Reliability

  7. VALIDITY vs. RELIABILITY Low Reliability, High Reliability, High Reliability, Low Validity Low Validity High Validity

  8. GOODNESS OF MEASURES TEST-RETEST RELIABILITY STABILITY RELIABILITY (Accuracy in measurement) PARALLEL-FORM RELIABILITY GOODNESS OF DATA INTERITEM CONSISTENCY RELIABILITY VALIDITY (Are we measuring the right thing?) CONSISTENCY SPLIT –HALF RELIABILITY LOGICAL VALIDITY (CONTENT) CRITERION-RELATED VALIDITY CONGRUENT VALIDITY (CONSTRUCT)) PREDICTIVE CONVERGENT FACE VALIDITY DISCRIMINANT CONCURENT

  9. RELIABILITY • Indicates the extent to which the measure is without bias (error free) and hence offers consistent measurement across time and across the various items in the instrument. • In other words, the reliability of measure indicates the stability and consistency with which the instrument measures the concept and helps to assess the “goodness” of measure.

  10. TEST-RETEST RELIABILITY The Reliability coefficient obtained with a repetition of the same measure on a second occasion. PARALLEL-FORM RELIABILITY When responses on two comparable sets of measures tapping the same construct are highly correlated. STABILITY OF MEASURES

  11. TEST-RETEST RELIABILITY If infrastructure in the country is not good, your company will cancel your decision to do Foreign Direct Investment (FDI) in that following country. Answer (now): strongly disagree Answer (20 days later): agree Low Reliability

  12. PARALLEL-FORM RELIABILITY Do you think that Susi Similikiti is beautiful? Answer: YES Do you think that Tukul’s wife is beautiful? Answer: NO Fact: Susi Similikiti is Tukul’s wife. Low Reliability

  13. INTERITEM CONSISTENCY This the test of the consistency of respondents’ answer to all the items in the measure. SPLIT-HALF RELIABILITY Reflecting the correlations between two halves of an instrument. CONSISTENCY

  14. PROBLEMS and PITFALLin VALIDITY

  15. VALIDITY in QUESTIONAIRE DESIGN • How diligent are you? 5 = very diligent 4 = diligent 3 = indifferent 2 = lazy 1 = very lazy Because respondents have to evaluate themselves, they tend to choose number (4) and (5), or at least number (3). Low Validity

  16. To measure the degree of diligent(as a student),we also can use this questionaire: • How much time do you spend to learn everyday? • How many books do you read every week? • How often do you go to library every week? The answer which revealed from questionaireabove will tend to be more accurate to measure the degree of diligent. High Validity

  17. Avoid question that ask two things at once, you won’t know which ‘bit’ people are answering: Low Validity

  18. Avoid ambiguity: Apakah kalian sudah membeli buku sejarah demokrasi yang baru? Apanya yang baru??? Bukunya...??? Sejarahnya...??? Atau... Demokrasinya??? Low Validity

  19. Avoid jargon/abbreviations/slang: Higher number of current GDP in a country will encourage your company to do more FDI in that country. Higher number of current Per capita Income in a country will make your company do more FDI in that country. If the level of corruption in a country increased, your company will reduce their amount of FDI in that country. Low Validity

  20. Avoid not mutually exclusive options: I’m 20 years old now. What age are you? 16-20  20-25  25-30  35-40  Low Validity

  21. Problems and Pitfalls • Avoid making questionnaire too long • Typographical / spelling errors Low Validity

  22. Using SPSS Analyze >>> Scale >>> Reliability Scale If item delete >>> Continue >>> OK If Corrected Item-Total Correlation > r-table: VALID If Cronbach’s Alpha if item deleted > r-table: RELIABEL

  23. Using SPSS

  24. THANK YOU!!!

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