All the data were entered into the spss spreadsheet and using the. In addition, kr20 computes the item difficulty proportion of right answers, the average value of item difficulty, the item variance, the itemtest pointbiserial correlation coefficients, and the average value of itemtest correlation coefficients. In psychometrics, the kuderrichardson formula 20 kr20, first published in 1937, is a measure of internal consistency reliability for measures with. Estimates internal consistency reliability given the mean m, standard deviation sd and k the number of items from a specific measure of interest. Kuder richardson formula 20 kr 20 and kuder richardson formula 21 kr 21. Stata module to calculate kuderrichardson coefficient. 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. Using and interpreting cronbachs alpha university of. Kuder and richardson formula 20 real statistics using excel. Kr20 reliability formula is used to calculate the internal consistency of an achievement. Only use the kr 20 if each item has a right answer. A generalization of kuderrichardson reliability formula.
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. There are two slightly different versions based on different statistical assumptions. This calculates kuder richarson 20 for a given matrix or ame. Spss software version 20 and its statistical interpretation. Kuder richardson reliability, kuder richardson formula 20. Sas and spss macros to calculate standardized cronbachs alpha.
Kr20 kudarrichardson 20 professional statistician for hire. Cronbach has given a formula to find out the reliability by using standard deviations of the scores not only on odd and even items but also the total number of items is as follows. When jamovi is calculating cronbachs alpha for internal consistency reliability does it switch to using the kr 20 formula kuder richardson 20 when it detects that the measures are dichotomous. My understanding is that spss does this because cronbachs alpha isnt appropriate for dichotomous variables and just wondering if jamovi did. The formula for cronbachs alpha builds on the kr20 formula to make it suitable for items with scaled responses e. The measure can be viewed as an extension of the kuderrichardson formula 20 kr20, which is an equivalent measure for dichotomous items. I am having an issue with kr20 am using alpha on spss but i have read that. 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. Hi everybody, 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. Statistics that are reported by default include the number of cases, the number of items, and reliability estimates as follows. Results obtained by the kudar richardson formula 20 adapted for use with rkw scoring are compared with three other reliability formulas. Calculating difficulty, discrimination and reliability index.
I use the kr20 instead of the cronbachs alpha because my items are noted on a binary scale. Calculating difficulty, discrimination and reliability. Computes the reliability coefficient of a set of dichotomous items, whereas cronbachs alpha is used for multipoint scales. Simple procedures for estimating interrater reliability are presented using the new spss for windows 5. Reliability refers to how consistent the results from the test are, or how well the test is actually measuring what you want it to measure. As these are measures of internal consistency, they measure the extent to which all the items measure the same. Can spss calculate the kuder richardson 20 kr20 and kr21 coefficients of reliability for a scale.
Kuderrichardson formulas 20 and 21 sage research methods. A generalization of kuderrichardson reliability formula 21 show all authors. Instrument reliability educational research basics by. Item analysis technique to improve test items and instruction 2. Identifies distractors not doing what they are supposed to do. The data is in and the numbers tell an interesting story. Dec 19, 2012 performing a reliability analysis on a measurement tool in which the items are dichotomous. Education software downloads spss by ibm and many more programs are available for instant and free download. Kuder and richardson 1937 first suggested the formula, and it is called kuder richardson formula 20 kr 20.
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 kr 20 formula calculations values for kr21 calculation coefficients range from 0. May 25, 2012 dear all, i am checking how to do a kuderrichardson reliability coefficients kr20 in spss. Dear all, i am checking how to do a kuderrichardson reliability coefficients kr20 in spss. Pada bahasan kali ini kita tidak membahas lebih lanjut tentang rumus kr ini, karena akan dijelaskan pada postingan artikel berikutnya. This video demonstrates how to perform a kuder richardson 20 kr 20 test of internal consistency in spss. Kuder richardson formula kr20 and the kuder richardson formula 21 kr21. Find out how the hesi rn exit exam and hesi rn specialty exams rated on the kuder richardson 20 kr20 scale for test reliability in 20172018. Case iv of the kuder richardson series, their formula 21, is derived as a generalized splithalf spearmanbrown coefficient. Hi everybody, i need to calculate internal consistency reliability, using kuderrichardson formula 20 i was wondering if someone can explain how to calculate it using spss 20. Alpha is a general version of the kuderrichardson coefficient of equivalence. The kr 20 is used to evaluate internal consistency among dichotomous variables.
Both kr formula 20 and kr formula 21 were used to estimate reliability on each test. I want to use the kr20 to learn about the internal consistency of items. Apr 02, 2015 kuder and richardson formula 20 reliability index. Excel spreadsheet to calculate instrument reliability. In psychometrics, cronbachs alpha coefficient of reliability in the special case of a scale with passfail, yesno, or other dichotomous test items. Describes how to calculate the kuder and richardson formula 20 kr20 and. Pdf determination of reliability and validity measures of a. Psychology definition of kuder richardson formulas. Kudar richardson 20 cannot be used for response sets that have three or more levels. View or download all content the institution has subscribed to. Kaiser 1960 rationale the suggestion by kaiser 1960 was based on a commonly used formula for the reliability of a total score. Correlation between forms, guttman splithalf reliability, spearmanbrown reliability equal and unequal length, and coefficient alpha for each half. Statistics definitions kuderrichardson formula 20 kr20. Rumus kr 20 dan tutorial cara hitung dengan excel uji.
It is important to evaluate the process of learning. Performing a reliability analysis on a measurement tool in which the items are dichotomous. Best for normreferenced tests comparing students within. 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. Penjelasan uji reliabilitas instrumen lengkap uji statistik. 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. 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. The kr 20, or kuder richardson formula, measures overall test reliability. The name of this formula stems from the fact that is the twentieth formula discussed in kuder and richardson s seminal paper on test reliability.
Formula 21 is a simplified and easily computable version of. Kuderrichardson reliability coefficients kr20 in spss. Ranges from 01 the higher the better greater than 0. Secondly, i appologize for linking a file but i could not get the fonts for the formula right.
Krl 20 and kr21 only work when data are entered as 0 and 1. Kuderrichardson 20 kr20 scale reliability calculation can spss calculate the kr20 reliability figure for assessing scales that are composed of dichotomous items. You can download it rs 12 calculating reliability of a measure. Item analysis with spss software linkedin slideshare. This measure of internal consistency provides an index of the homogeneity of responses to the unidimensional construct underlying the variables or. Often discussed in tandem with kr 20, is kuder richardson formula 21 kr21. Kr20 kuderrichardson formula 20 is an index of the internal consistency reliability of a measurement instrument, such as a test, questionnaire, or inventory. Psychometric validity and reliability statistics in r. Kuderrichardson formula 21 calculator for test reliability. Kuderrichardson formula 20, or kr 20, is a measure reliability for a test with binary variables i. What the formla does is to estimate test reliability.
The spearmanbrown prophecy formula is applied to the correlation to determine the reliability. Kr21 is a simplified version of kr 20, which can be used when the difficulty of all items on the test are known to be equal. Untuk perhitungan koefisien reliabilitas dapat dilakukan dengan menggunakan rumus kuder richardson kr 20 dan kuder richardson kr21. What is the difference between kuderrichardson kr20 and cronbachs alpha and how do you formulate both. Conducting a kuderrichardson 20 test kr20 in spss youtube. Note that the matrix or ame should be at the item level and that it needs to be numeric not characters or factors. The kuder richarson formula 20, often abbreviated as kr 20, and the kuder richardson formula 21, abbreviated kr21, are measures of internal consistency for measures that feature dichotomous items. Kudar richardson 20 is run the exact same way as cronbachs alpha in spss and interpreted the same way as well. Reliability coefficients lambda 1 through lambda 6. Apr 26, 2006 it was first named as alpha by cronbach 1951, although an earlier version is the kuder richardson formula 20 often shortened to kr 20, which is the equivalent for dichotomous items, and guttman 1945 developed the same quantity under the name lambda2. Oct 25, 2015 this video demonstrates how to perform a kuder richardson 20 kr 20 test of internal consistency in spss. Can some one please tell me when i can use the kurder richardson 21 formula, kr20 coefficient alpha or spearmanbrown formula to calculate the reliability coefficient of a test.
Should i use kr20 or kr21 to calculate the reliability. The reliability estimates are incorrect if you have missing data. Sas and spss macros have been developed in this article to obtain standardized cronbachs. Berikut dibawah ini adalah rumus kuder richardson 20. Kuder richardson 20 use to calculate for the formula kr20 reliability of the test in which the items are dichotomous, scored 0 or 1 usually for right or wrong sum of the product of people passing each item times the proportion of people failing each item. You can select various statistics that describe your scale and items. In psychometrics, the kuder richardson formula 20 kr 20, first published in 1937, is a measure of internal consistency reliability for measures with dichotomous choices. The basic assumption employed is shown to be sufficient to justify the various assumptions used in derivations by other authors.
The reliability procedure can calculate alpha and therefore can calculate kr20 for binary item. What is the difference between kuderrichardson kr20 and. Differences between kuderrichardson formula 20 and formula. Feb 27, 2012 simple procedures for estimating interrater reliability are presented using the new spss for windows 5. Kuderrichardson 20 kr20 scale reliability calculation. The approximate sampling distribution of kuderrichardson. A correct question scores 1 and an incorrect question scores 0. The kuder and richardson formula 20 test checks the internal consistency of measurements with dichotomous choices. Using reliability, validity, and item analysis to evaluate. 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. 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. The kr20 is a special case of cronbachs alpha in which the items are binary variables usually scored as 0 or 1.
The findings suggest that in order to measure students performance effectively, necessary. Kuderrichardson reliability coefficients kr20 and kr21. How to use spss kuderrichardson20 kr20 reliability. The kr20, or kuderrichardson formula, measures overall test reliability. Kuderrichardson reliability coefficients kr20 and kr21 ibm. A note on the estimation of test reliability by the kuder. The kudar richardson 20 kr 20 formula generates a raw reliability coefficient for survey items that use these response sets. Kr20 kuder richardson formula 20 is an index of the internal consistency reliability of a measurement instrument, such as a test, questionnaire, or inventory. Both the interrater reliability for averaged ratings and the intraclass correlation for a single, typical judge are derived from the repeated. Kuder richardson formula 20 in its general form is known as efficient. It was first named alpha by lee cronbach in 1951, as he had intended to continue with further coefficients. 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. An example of such a set of commands is provided below, however, kr20 is generally considered to be a better reliability estimate than kr21. The eigenvaluesgreaterthanone rule and the reliability.
Differences between kuderrichardson formula 20 and. Rumus kr 20 dan tutorial cara hitung dengan excel uji statistik. Kuder richardson formula 20, or kr 20, is a measure reliability for a test with binary variables i. I have created an excel spreadsheet to automatically calculate splithalf reliability with spearmanbrown adjustment, kr 20, kr21, and cronbachs alpha. Kr20 kuderrichardson formula 20 is an index of the internal consistency reliability of a measurement instrument, such as a test.
Use spearmanbrowns formula to correct problems of shortness, enabling correlation as if each part were full length. It was first named as alpha by cronbach 1951, although an earlier version is the kuder richardson formula 20 often shortened to kr 20, which is the equivalent for dichotomous items, and guttman 1945 developed the same quantity under the name lambda2. This is often used with dichotomous variables that are scored 0 for incorrect and 1 for correct. 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 program. Can spss calculate the kuderrichardson 20 kr20 and kr21 coefficients of reliability for a scale. If all of the scale items you want to analyze are binary and you compute cronbachs alpha, youre actually running an analysis called the kuderrichardson 20.
Online statistics helps you in estimating the test reliability using kuderrichardson formula 21 calculator. Reliability, kuderrichardson formulapage 1418 sage. The kuder richardson formula 21 as a splithalf coefficient, and some remarks on its basic assumption. Essentially it lets you know whether the exam as a whole discriminated among students who mastered the subject matter and those who did not. This video demonstrates how to perform a kuderrichardson 20 kr20 test of internal consistency in spss. It is equivalent to performing the split half methodology on all combinations of questions and is applicable when each question is either right or wrong. The most useful measure is generally the kuder richardson formula 20 kr 20.