Using and interpreting cronbachs alpha university of. If the variances of the items vary widely, you can standardize the items to a standard deviation of 1 before computing the coefficient alpha. To that end, it is necessary to test the validity and reliability to determine whether the instrument used in the study are valid and reliable. Ive heard some individuals tell others that they must use a kuder. Although it can be applied to any test item responses that are dichotomously scored, it is most often used in classical psychometric analysis of psychoeducational tests and, as such. This is a measure of the likelihood of obtaining similar results if you readminister the exam to another group of similar students. The kuder richarson formula 20, often abbreviated as kr20, and the kuder richardson formula 21, abbreviated kr21, are measures of internal consistency for measures that feature dichotomous items.
It is important to evaluate the process of learning, teacher performance and impact of the software to achieve meaningful learning, as a measure to detect deficiencies and feedback to the process. Sage reference reliability, kuderrichardson formula. Spss software version 20 and its statistical interpretation. Pdf determination of reliability and validity measures of a. After the initial run the program prints the proportion of correct responses for each item and the kuder richardson reliability coefficient kr20 and kr21, plus the number of examinees that omitted each item and the number that reached each item. I have created an excel spreadsheet to automatically calculate splithalf reliability with spearmanbrown adjustment, kr20, kr21, and cronbachs alpha. The length of the test a test with more items will have a higher reliability, all other things being equal. Untuk perhitungan koefisien reliabilitas dapat dilakukan dengan menggunakan rumus kuder richardson kr20 dan kuder richardson kr21. How to use spss kuderrichardson20 kr20 reliability. The cronbach alpha coefficient is calculated, but if it is nominal data yes, no the statistical equivalent to the cronbach coefficient is the kr20 of kuder richardson alfa model. I use the kr20 instead of the cronbachs alpha because my items are noted on a binary scale. Determine the reliability of the questionnaire using kuder and richardson formula 20. In psychometrics, cronbachs alpha coefficient of reliability in the special case of a scale with passfail, yesno, or other dichotomous test items.
In psychometrics, the kuderrichardson formula 20 kr20, first published in 1937, is a measure of internal consistency reliability for measures with dichotomous choices. Using reliability, validity, and item analysis to evaluate. The kudar richardson 20 kr20 formula generates a raw reliability coefficient for survey items that use these response sets. I need to calculate internal consistency reliability, using kuder richardson formula 20 i was wondering if someone can explain how to calculate it using spss 20. The name of this formula stems from the fact that is the twentieth formula discussed in kuder and richardsons seminal paper on. Consistency is a measure of reliability through similarity within the test, with individual questions giving predictable answers every time. Ranges from 01 the higher the better greater than 0. Results obtained by the kudar richardson formula 20 adapted for use with rkw scoring are compared with three other reliability formulas. How to do statistical analysis for test test reliability.
Differences between kuderrichardson formula 20 and formula. If, in addition to measuring internal consistency, you wish to. Reliability coefficients lambda 1 through lambda 6. The kuder richardson formula kr20 and the kuder richardson formula 21 kr21. Expanding the possibilities for continual improvement the kr20, or kuder richardson formula, measures overall test reliability essentially it lets you know whether the exam as a whole discriminated. Using reliability, validity, and item analysis to evaluate a. Kr20 kuderrichardson formula 20 is an index of the internal consistency reliability of a measurement instrument, such as a test, questionnaire, or inventory. The approximate sampling distribution of kuderrichardson. Simple procedures for estimating interrater reliability are presented using the new spss for windows 5. A note on the estimation of test reliability by the kuder.
The use of the theoretical distribution for testing hypotheses. Two statistical tests were used to compute the reliability of the test. Kuder richardson 21 calculator chisquare calculator. Kuderrichardson reliability coefficients kr20 in spss. Stata module to calculate kuder richardson coefficient of reliability, statistical software components s351001, boston college department of economics, revised 14 sep 1999. Based on parallel tests administered at the same sitting the kr 20 estimates are compared with alternateform correlations and with oddeven correlations adjusted by the spearmanbrown prophecy formula. Kuderrichardson 20 kr20 scale reliability calculation. Both kr20 and cronbachs alpha are measures of internal consistency broadly referred to as coefficient alpha. Excel spreadsheet to calculate instrument reliability. This formula is often referred to as kuder richardson formula 20, or kr20. Cronbachs alpha continuous and dichotomous data in spss. A high value for alpha does not imply that the measure is unidimensional. Kudar richardson 20 is run the exact same way as cronbachs alpha in spss and interpreted the same way as well. Learn vocabulary, terms, and more with flashcards, games, and other study tools.
Rumus kr 20 dan tutorial cara hitung dengan excel uji. So, you can get what you need from the reliability procedure. There are two slightly different versions based on different statistical assumptions. Psychometric validity and reliability statistics in r. Can spss calculate the kuder richardson 20 kr20 and kr21 coefficients of reliability for a scale. Online statistics helps you in estimating the test reliability using kuderrichardson formula 21 calculator. Pada bahasan kali ini kita tidak membahas lebih lanjut tentang rumus kr ini, karena akan dijelaskan pada postingan artikel berikutnya. A metaanalytic method that combines estimates of reliability across studies in order to calculate an estimate based on multiple indicators of reliability. Spearmanbrown formula a formula for correcting a splithalf reliability coefficient that estimates what the coefficient would be if the original number of items were used. If we use the results from our orthogonal rotation look back at.
Some of the popular software systems such as spss do have reliability procedures to compute reliability of an instrument. A correct question scores 1 and an incorrect question scores 0. Reliability, kuderrichardson formulapage 1418 sage. Suppose you make up a multiple choice personality test that decides a yesno question, like do you belong in slytherin house. Splithalf and cronbachs alpha work with likert scale.
Check all that apply spearmanbrown kuder richardson kr20 cronbachs alpha. Dear all, i am checking how to do a kuderrichardson reliability coefficients kr20 in spss. Oct 25, 2015 this video demonstrates how to perform a kuder richardson 20 kr20 test of internal consistency in spss. An approximation to the sampling distribution of kuder richardson reliability formula 20 is derived, using its algebraic equivalent obtained through an itemsbysubjects analysis of variance. What is the kuderrichardson test for reliability and what do.
The kr20 is used to evaluate internal consistency among dichotomous variables. A collection of reliability measures was introduced by kuder and richardson, 1937. A statistic that provides an indication of the degree to which two sets of scores are related. Kr20 kuder richardson formula 20 is an index of the internal consistency reliability of a measurement instrument, such as a test, questionnaire, or inventory.
Analyzescale reliability analysis dragplace variables to item box statistics scale. It is a measure of how difficult the question was to answer. The kuderrichardson formula 20 is rewritten to be identical with the simplest formula, 21, except for the addition of a term involving the standard deviation. May 25, 2012 dear all, i am checking how to do a kuderrichardson reliability coefficients kr20 in spss. Conducting a kuderrichardson 20 test kr20 in spss youtube. It assess the intern consistency reliability of a test of subtest made up of binary items, two psychometric methods, kuder richardson formula 20. Figure 1 kuder and richardson formula 20 for example 1 the values of p in row 18 are the percentage of students who answered that question correctly e. Although some recommend using the kr20 kuder richardson coefficient if the data are dichotomous, cronbachs coefficient alpha and kr20 yield the same value. What is the difference between kuderrichardson kr20 and. The content of the test generally, the more diverse the subject matter tested and the testing techniques used, the lower the reliability. Calculating difficulty, discrimination and reliability. Both the interrater reliability for averaged ratings and the intraclass correlation for a single, typical judge are derived from the repeatedmeasures anova output in the reliability. Eric ed074095 an assessment of the kuderrichardson.
If, in addition to measuring internal consistency, you wish to provide evidence that the scale. Correlation between forms, guttman splithalf reliability, spearmanbrown reliability equal and unequal length, and coefficient alpha for each half. Remember also that i said we should conduct reliability analysis on any subscales individually. As these are measures of internal consistency, they measure the extent to which all the items measure the same characteristic. Kudarrichardson 20 kr20 is an internal consistency measure of reliability for survey items using dichotomous response sets. Rumus kuder richardson 20 apabila pada artikel sebelumnya kita sudah membahas cara perhitungan reliabilitas instrumen dengan excel yang meliputi uji cronbach alpha, split half dan spearman brown, maka dalam artikel ini kita akan membahas cara perhitungan rumus kr 20 dengan menggunakan excel. A computer program for estimating examinee ability. Reliability test were also conducted in addition to the item analysis to observe the quality of the test as a whole. How to test reliability method alpha using spss spss tests. Estimates internal consistency reliability given the mean m, standard deviation sd and k the number of items from a specific measure of interest. Apr 28, 2018 how to test reliability method alpha using spss instruments are valid and reliable research is a necessary condition to obtain highquality research results. They did not give the reliability coefficients particular names.
Cronbachs alpha is a measure of internal consistency, that is, how closely related a set of items are as a group. If you give the test to a bunch of people, you can use the kuder richardson test on their results to try to tell you s. Psychology definition of kuder richardson formulas. Stata module to calculate kuderrichardson coefficient. Note that the matrix or ame should be at the item level. It is considered to be a measure of scale reliability. Kr20 read about our exciting partnership with blackboard, inc. In other words, the reliability of any given measurement refers to the extent to which it is a consistent measure of a concept, and cronbachs alpha is. Rumus kr 20 dan tutorial cara hitung dengan excel uji statistik. Consistency can be measured with splithalf testing and the kuder richardson test. Kr20 is a special computational case of cronbachs alpha. Item analysis with spss software linkedin slideshare. Reliability assessment of a survey instrument ramesh m. Item analysis technique to improve test items and instruction.
Penjelasan uji reliabilitas instrumen lengkap uji statistik. The reliability estimates are incorrect if you have missing data. Determination of reliability and validity measures of a questionnaire. Reliability analysis on spss lets test the reliability of the saq using the data in saq. It assess the intern consistency reliability of a test of subtest made up of binary items, two psychometric methods, kuder richardson formula 20 9kr 20. Note that the matrix or ame should be at the item level and that it needs to be numeric not characters or factors. An example of such a set of commands is provided below, however, kr20 is generally considered to be a better reliability estimate than kr21. If the variables are dichotomous 0,1, the coefficient alpha is equivalent to the kuder richardson 20 kr20 reliability measure. I want to use the kr20 to learn about the internal consistency of items. The values of p in row 18 are the percentage of students who answered that question correctly e.
To investigate the effect of violating the assumption of equal item difficulty on kuder richardson kr formula 21 reliability coefficient, 670 eighthand ninth grade students were administered 26 short, homogeneous tests of mathematics concepts and skills. This calculates kuder richarson 20 for a given matrix or ame. Kuderrichardson reliability coefficients kr20 and kr21. This index checks the internal consistency of measurements with dichotomous choices i. The theoretical distribution is compared to empirical estimates of the sampling distribution to assess how crucial certain assumptions are. Final output contains the estimated item parameters and abilities, printed and punched. Now, you should have reverse scored item 3 see above. In psychometrics, the kuder richardson formula 20 kr20, first published in 1937, is a measure of internal consistency reliability for measures with dichotomous choices. The results are listed in the upper portion of figure 1. This video demonstrates how to perform a kuder richardson 20 kr20 test of internal consistency in spss. The most useful measure is generally the kuder richardson formula 20 kr20.
The kr21 could be calculated in spss by using the aggregate procedure to save kr21 formula components to an active file, where they could be input into a compute command to calculate kr21. How to use spss kuder richardson 20 kr20 reliability analysis. In other words, the reliability of any given measurement refers to the extent to which it is a consistent measure of a concept, and cronbachs alpha is one way of measuring the strength of that consistency. Kuder and richardson formula 20 real statistics using excel. Kuder and richardson 1937 kuder and richardson 1937 developed several reliability coefficients that could overcome the problem of. The kr21 formula for reliability is a conservative estimate of internal reliability due to the fact that kr21 results will yield lower data numbers than that of kr20 formula calculations values for kr21 calculation coefficients range from 0.
How to do statistical analysis for test test reliability of a. A break variable does not need to be designated in current versions of spss statistics when the aggregation is performed over the full data set. Cronbachs alpha is a measure used to assess the reliability, or internal consistency, of a set of scale or test items. Figure 1 kuder and richardson formula 20 for example 1. Kudar richardson 20 cannot be used for response sets that have three or more levels. It is important to evaluate the process of learning. Krl20 and kr21 only work when data are entered as 0 and 1. What is the kuderrichardson test for reliability and what. Dec 19, 2012 how to use spss kuder richardson 20 kr20 reliability analysis. Allows you to compute the reliability and biserial and pointbiserial correlations using the.
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