For kr21 all you need is the mean score on the test, the standard deviation, and the number of items k. The kudar richardson 20 kr 20 formula generates a raw reliability coefficient for survey items that use these response sets. This chapter deals with some theoretical background of reliability and validity. Kuder and richardson formula 20 real statistics using excel. Calculating difficulty, discrimination and reliability. Item analysis technique to improve test items and instruction 2. The kr 20 is used to evaluate internal consistency among dichotomous variables. Differences between kuderrichardson formula 20 and formula. Stata module to calculate kuderrichardson coefficient. Ranges from 01 the higher the better greater than 0.
Although some recommend using the kr 20 kuder richardson coefficient if the data are dichotomous, cronbachs coefficient alpha and kr 20 yield the same value. Conducting a kuderrichardson 20 test kr20 in spss youtube. Describes how to calculate the kuder and richardson formula 20 kr20 and. It is considered more accurate than the kuder richardson 21. For dichotomous data, this is equivalent to the kuder richardson 20 kr20 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. This index checks the internal consistency of measurements with dichotomous choices i. How to use spss kuderrichardson20 kr20 reliability. The use of the theoretical distribution for testing hypotheses. An example of such a set of commands is provided below, however, kr20 is generally considered to be a better reliability estimate than kr21.
Apr 02, 2015 kuder and richardson formula 20 reliability index. Computes the reliability coefficient of a set of dichotomous items, whereas cronbachs alpha is used for multipoint scales. Kuder richardson formula 20 kr 20 and kuder richardson formula 21 kr 21 these are alternative formulas for calculating how consistent subject responses are among the questions on an. Kuder richardson formula 20 21 correlation is determined from a single administration of a test through a study of score. Both kr formula 20 and kr formula 21 were used to estimate reliability on each test. Kudar richardson 20 cannot be used for response sets that have three or more levels. Spss is not freeware, and besides windows, you can download the linux version, as well. Can spss calculate the kuderrichardson 20 kr20 and kr21 coefficients of reliability for a scale. The formula for cronbachs alpha builds on the kr 20. Online statistics calculator which helps you in estimating test reliability from the given values.
For instance, the spss program can calculate kr20 as a special case of cronbachs alpha. Kuderrichardson formula 20 21 correlation is determined from a single administration of a test through a. Kuderrichardson 20 kr20 scale reliability calculation. 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.
Correlation between forms, guttman splithalf reliability, spearmanbrown reliability equal and unequal length, and coefficient alpha for each half. Item analysis with spss software linkedin slideshare. For tests with equal item loadings, alpha g6, but if the loadings are unequal or if there is a general factor, g6 alpha. Just copy and paste the below code to your webpage where you want to display this calculator. Alpha should be calculated whenever possible, but kr21 can provide reasonable reliability estimates for tests with dichotomous items. Using and interpreting cronbachs alpha university of. Rentang nilainya berada diantara 0 sampai dengan 1.
This formula is often referred to as kuderrichardson formula 20, or kr20. 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. This video demonstrates how to perform a kuderrichardson 20 kr20 test of internal consistency in spss. 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. 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. Kuder richardson 21 this statistic approximates inter. This video demonstrates how to perform a kuder richardson 20 kr 20 test of internal consistency in spss.
The formula for cronbachs alpha builds on the kr20 formula to make it suitable for items with scaled responses e. Sep 15, 2015 in this article learn how to use spss software to analyze data for research paper. 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. I have calculated the cronbachs alpha for my dichotomous test. Pada bahasan kali ini kita tidak membahas lebih lanjut tentang rumus kr ini, karena akan dijelaskan pada postingan artikel berikutnya. Krl20 and kr21 only work when data are entered as 0 and 1. Correlation between forms, guttman splithalf reliability, spearmanbrown 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. Estimates internal consistency reliability given the mean m, standard deviation sd and k the number of items from a specific measure of interest.
Rumus kr 20 dan tutorial cara hitung dengan excel uji. The kudarrichardson 20 kr20 formula generates a raw reliability coefficient for survey items that use these response sets. Expanding the possibilities for continual improvement the kr20, or kuder richardson. Penjelasan uji reliabilitas instrumen lengkap uji statistik. Using reliability, validity, and item analysis to evaluate a. The most useful measure is generally the kuderrichardson formula 20 kr20. 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. Performing a reliability analysis on a measurement tool in which the items are dichotomous. Apr 07, 2020 i need to use cronbachs alpha to checkprovecalculate the reliability of my test. Online statistics helps you in estimating the test reliability using kuder richardson formula 21 calculator. Stata module to calculate kuder richardson coefficient of reliability, statistical software components s351001, boston college department of economics, revised 14 sep. Kudarrichardson 20 cannot be used for response sets that have three or more levels.
May 25, 2012 dear all, i am checking how to do a kuderrichardson reliability coefficients kr20 in spss. The formula for cronbachs alpha builds on the kr 20 formula to make it suitable for items with scaled responses e. Reliability, kuderrichardson formulapage 1418 sage. 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. Spss software version 20 and its statistical interpretation. Kr 20 kuder richardson formula 20 is an index of the internal consistency reliability of a measurement instrument, such as a test, questionnaire, or inventory. I have gone through testretest methodprocedure and i have administered the test twice with an interval. Kuder richardson 20 kr20 scale reliability calculation can spss calculate the kr20 reliability figure for assessing scales that are composed of dichotomous 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. Dear all, i am checking how to do a kuderrichardson reliability coefficients kr20 in spss.
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. Kuderrichardson reliability coefficients kr20 and kr21 ibm. The most useful measure is generally the kuder richardson formula 20 kr 20. Kuderrichardson 20 kr20 scale reliability calculation can spss calculate the kr20 reliability figure for assessing scales that are composed of dichotomous items. Kudarrichardson 20 kr20 is an internal consistency measure of reliability for survey items using dichotomous response sets. How do i compute the internal consistency of a scale which is. I use the kr20 instead of the cronbachs alpha because my items are noted on a binary scale. You can use spss reliability command to calculate kr20 just. The spss or any other statistical program should have the calculation of these. What is the difference between kuderrichardson kr20 and cronbachs.
The kuder richardson 20 will always be greater or equal to the kuder richardson 21. A correct question scores 1 and an incorrect question scores 0. If the variances of the items vary widely, you can standardize the items to a standard deviation of 1 before computing the coefficient alpha. The findings suggest that in order to measure students performance effectively, necessary. It is also appropriate for dichotomous items, so can be used instead of kuder richardson 20. Thermuohp biostatistics resource channel 101,144 views. The theoretical distribution is compared to empirical estimates of the sampling distribution to assess how crucial certain assumptions are. Education software downloads spss by ibm and many more programs are available for instant and free download. The kr 20, or kuder richardson formula, measures overall test reliability. Excel spreadsheet to calculate instrument reliability. I want to use the kr20 to learn about the internal consistency of items.
Kudarrichardson 20 is run the exact same way as cronbachs alpha in spss. Often discussed in tandem with kr 20, is kuder richardson formula 21 kr21. Consistency can be measured with splithalf testing and the kuder richardson test. Dividing the test into two usually a midpoint, oddeven numbers, random or other method administering them as separate tests. If the variables are dichotomous 0,1, the coefficient alpha is equivalent to the kuder richardson 20 kr 20. The basic assumption employed is shown to be sufficient to justify the various assumptions used in derivations by other authors.
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. Instrument reliability educational research basics by. A high kr 20 indicates reliable consistent student scores. Kuderrichardson reliability coefficients kr20 in spss.
Cronbachs alpha continuous and dichotomous data 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. Apr, 2011 there youll see that cronbach actually stole hoyts idea for reliability when he created his coefficient alpha and both took it from the kuder richardson formula 20 so nothings new under the sun, lol. If all of the scale items you want to analyze are binary and you compute cronbachs alpha, youre actually running an analysis called the kuder richardson 20. How do i compute the internal consistency of a scale which. Selection of items various tryouts, final run of the tests were discussed. The reliability estimates are incorrect if you have missing data. Untuk perhitungan koefisien reliabilitas dapat dilakukan dengan menggunakan rumus kuder richardson kr 20 dan kuder richardson kr21. Essentially it lets you know whether the exam as a whole discriminated among students who mastered the subject matter and those who did not. Splithalf and cronbachs alpha work with likert scale. The kuderrichardson formula 21 as a splithalf coefficient. Calculating difficulty, discrimination and reliability index. 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.
Please, can anyone tell me how to write the kuder richardson stata command or to reach it through menus, other than using alpha. 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. Kr20 read about our exciting partnership with blackboard, inc. Kr 20 kr 20 are measures of test reliability, kuder richardson formula 20, or kr 20, is a measure reliability for a test with binary variables i. Results obtained by the kudar richardson formula 20 adapted for use with rkw scoring are compared with three other reliability formulas. They dealt with cases where the observed scores were dichotomous e. Should i use kr20 or kr21 to calculate the reliability. Stata module to calculate kuder richardson coefficient of reliability, statistical software components s351001, boston college department of economics, revised 14 sep 1999. The name of this formula stems from the fact that is the twentieth formula discussed in kuder and richardson. Kuderrichardson formula 21 calculation for test reliability. Kudar richardson 20 is run the exact same way as cronbachs alpha in spss and interpreted the same way as well.
The approximate sampling distribution of kuderrichardson. Conducting a kuder richardson 20 test kr 20 in spss duration. 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. How can reliability coefficient uding kr20 or kr21 be determined. I have created an excel spreadsheet to automatically calculate splithalf reliability with spearmanbrown adjustment, kr 20, kr21, and cronbachs alpha. Kuderrichardson formula 20, or kr20, is a measure reliability for a test with. Berikut dibawah ini adalah rumus kuder richardson 20. How to use spss software to analyze data for research paper. Online statistics helps you in estimating the test reliability using kuderrichardson formula 21 calculator. Case iv of the kuder richardson series, their formula 21, is derived as a generalized splithalf spearmanbrown coefficient. I used ibm spss statistics v19 on my 64bit windows 8. Then i came across the kuder and richardson formula 20 that is basically a simplification of the cronbachs alpha, appropriate for. Kuderrichardson reliability coefficients kr20 and kr21.
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