Cronbachs alpha values are quite sensitive to the number of items in the scale. Alphamax is an spss and sas macro that generates all possible subscales of at least two items from an additive scale containing k items. Reliability is normally reported under the head of instrumentation in the methodology section. Cara melakukan uji reliabilitas alpha cronbachs dengan spss. Andy field page 4 2152006 finally, and perhaps most important, the value of alpha at the very bottom is the cronbachs alpha. Dalam program spss metode yang sering digunakan untuk uji reliabilitas adalah dengan menggunakan metode alpha cronbach s. In order to measure cronbach alpha for reliability, you can go back to mainstream statistical software like spss etc. If you need to learn more about cronbach s alpha, click here to read it. For each possible subscale, it generates cronbach s alpha and the subscalefull scale correlation and displays information about each subscale in a data spread sheet. Reliability analysis example portland state university. It was first named alpha by lee cronbach in 1951, as he had intended to continue with further coefficients. Can i use cronbach s alpha to establish the internal consistency of the said scale.
Ordinal alpha is an alternative to cronbach s alpha that is more accurate with likertscale responses. Stata does not included baked in calculations of ordinal alpha. Instrumen dapat dikatakan reliabel bila nilai cronbachs alpha lebih besar dari r tabel. Making sense of cronbachs alpha pubmed central pmc. This model computes guttmans lower bounds for true reliability. Cronbach s alpha is certainly among the most used statistics in the social sciences, but many students and researchers dont really know what it tells us or how to interpret it. Uji reliabilitas spss adalah pengujian yang mengukur tingkat konsisten atau kestabilan data kuesioner menggunakan software spss.
Cronbach alpha is a reliability test conducted within spss in order to measure the internal consistency i. Cara uji reliabilitas spss alpha cronbachs data kuesioner. Cronbach s alpha reliability test cronbach s alpha n of items 0. Table 3 shows the itemanalysis output from spss for the multiitem scale of student.
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. Analysing data using spss sheffield hallam university. Hence n of items in the below cronbachs alpha test is 48. Instrumen dapat dikatakan reliabel bila nilai cronbach s alpha lebih besar dari r tabel. Cronbach s alpha coefficient increases either as the number of items variables increases, or as the average interitem correlations increase i. The correlations between variables should be consistently high. Once you are familiar with cronbach s alpha, we can then use spss to calculate it. This model splits the scale into two parts and examines the correlation between the parts. Shall we measure the coefficient alpha separately for each variable or we. How does reliability measures work with smart pls path. Andy field page 4 2152006 finally, and perhaps most important, the value of alpha at the very bottom is the cronbach s alpha. In r, there are several packages that calculate cronbach s alpha.
Sas and spss macros to calculate standardized cronbachs. The above syntax will produce only some very basic summary output. It is most commonly used when the questionnaire is developed using multiple likert scale statements and therefore to. Eu preciso obter o valor geral e tambem o valor por fatores. The purpose of this paper is to show why singleitem questions pertaining to a construct are not reliable and should not be used in drawing conclusions. A high value of alpha is often used along with substantive arguments and possibly other statistical measures as evidence that the items measure an underlying or latent construct. Internal reliability of the 12item internet addiction scale was investigated using cronbach s alpha. Cronbachs alpha is a measure used to assess the reliability. For more information on cronbachs alpha, see spss library.
Pdf uji validitas dan reliabilitas berbantuan software. Uji dilakukan pada taraf signifikasi a sebesar 0,05. Examination of individual item statistics suggested. Calculating, interpreting, and reporting cronbachs alpha reliability coefficient for likerttype scales joseph a. Spss version 15 but this is now superseded by version 16 and version 17 is on its way. Cronbach s alpha measurement of internal consistency.
Analysis of the reliability and validity of a mentors. Enter the data into spss as shown above in table 3. Dalam program spss metode yang sering digunakan untuk uji reliabilitas adalah dengan menggunakan metode alpha cronbachs. This model is a model of internal consistency, based on the average interitem correlation. From table 3 we can see that the first student, student a, rated item tv1 a 4, rated item tv2 a 5, and item tv3 a 4. Generally, many quantities of interest in medicine, such as anxiety or degree. The method used to validate an instrument, internal consistency is cronbach s alpha, the same that is used in this work. The swissarmy knife of criteria for scale reliability is cronbach s alpha cronbach, 1951. It is generally used as a measure of internal consistency or reliability of a psychometric instrument.
Cronbachs alpha reliability analysis of measurement scales. Calculating, interpreting, and reporting cronbachs alpha. Spss users who have the missing values analysis addon module can obtain vectors of em means and standard. Exploratory factor analysis and reliability analysis with missing data. Cronbachs alpha in spss statistics procedure, output and. 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.
Hai, ida ayu brahmi, artikel ini dibuat pada tanggal 20180702t07. Cronbachs alphareliability test cronbachs alpha n of items 0. Then there are a few options which can be used to finetune the command. Spss once spss has opened up there are several options as to how to import your data o you can open it from an existing file o if the dataset is small, then you could type the dataset in by hand o you can run the tutorial as well as a few more option we will open an existing dataset. In other words, it measures how well a set of variables or items measures a single, onedimensional latent aspect of individuals. Cronbachs alpha using spss introduction cronbach s alpha is the most common measure of internal consistency reliability. Fortunately, chad marshall wrote a wonderful introduction to cronbachs alpha, below. Cronbach s alpha if item deleted we can see that removal of any question, except question 8, would result in a lower cronbach s alpha. Calculatingcronbachalpha reliabilitystatisticsinspssv. How to test reliability method alpha using spss instruments are valid and reliable research is a necessary condition to obtain highquality research results.
Coefficient alpha by cronbach is a measure of internal reliability or consistency of. Calculating total scale scores and reliability spss. Cronbach s alpha is the average value of the reliability coefficients one would obtained for all. A high value of a is often used along with substantive arguments and possibly other statistical measures as evidence that the.
Sekian artikel cara uji reliabilitas spss alpha cronbach s data kuesioner. Apr 26, 2017 cronbachs alpha is a measure of internal consistency, that is, how closely related a set of items are as a group. If cronbach s alpha for some subsets falls below 0. For more information about reading data in spss, see the spss command syntax reference. If the data contain no missing values, all packages i visited converge to the same value. The first important table is the reliability statistics table that provides the actual value for cronbach s alpha 8. In spss, how do i compute cronbachs alpha statistic to. Cronbachs alpha in spss statistics procedure, output. Hence n of items in the below cronbach s alpha test is 48. First of all, the reverse variable list causes stata to reverse score. Use one of the following procedures to install the data on your computer.
Reliability statistics cronbachs alpha cronbachs alpha based on standardized items n of items. Below are stepbystep commands for calculating cronbach s alpha in spss. In smartpls we can use composite reliability to measure reliability. Cronbach university of illinois a general formula a of which a special case is the kuder richardson coefficient of equivalence is shown to be the mean of all. For more information about intraclass coefficients as a measure of reliability, see spss library. Internal consistency and reliability were measured using cronbach s alpha. Chad marshall is currently a dba student in the mitchell college of business at the university of south alabama.
A total of 229 candidate internship scores were used. Cronbach s alpha in this tutorial you will learn how to produce a simple and commonly used measure of reliability. Cronbachs alpha is a measure used to assess the reliability, or internal consistency, of a set of scale or test items. Cronbachs alpha is most commonly used when you want to assess the internal consistency. Note i just adjusted the code to remove the first id column from the data frame which should not be submitted to the cronbach. Untuk variabel yang lain langkahlangkah uji validitas dan reliabilitas dengan spss sama dengan. Calculating, interpreting, and reporting cronbach s alpha reliability coefficient for likerttype scales joseph a. Cronbachs alpha is most commonly used when you want to assess the internal consistency of a questionnaire or survey that is. For more information on cronbach s alpha, see spss library. Cronbach s alpha reliability coefficient normally ranges between 0 and 1. Would be useful to calculate it by hand and using that function to make sure they are the same. Cronbachs alpha is the most common measure of internal consistency reliability.
Cronbach s is a function of the number of items in a test, the average covariance between itempairs, and the variance of the total score. Conduct and interpret an internal consistency reliability analysis through cronbachs alpha, the corrected itemtotal correlations and the. Cara melakukan uji reliabilitas alpha cronbachs dengan spss setelah sebelumnya kita telah melakukan uji validitas product momen dengan spss, selanjutnya yang harus kita lakukan agar angket yang digunakan dalam penelitian ini benarbenar dapat dipercaya sebagai alat pengumpul data, maka angket tersebut perlu di uji reliabilitas atau tingkat kepercayaannya. Sas and spss macros to calculate standardized cronbachs alpha using the upper bound of the phi coefficient for dichotomous items wei sun, chihping chou, a lan w. This article shows a practical example to determine the reliability of an instrument measuring student satisfaction in minitab software application, used as supplementary teaching. Cronbach s alpha is the most common measure of internal consistency reliability. Calculating cronbachs alpha in spss improving internal. The reliability test resulted in an overall alpha of.
Pengertian uji reliabilitas menurut sugiarto dan situnjuk 2006, uji reliabilitas reliability adalah pengujian yang menunjukkan apakah suatu instrumen yang digunakan untuk memperoleh. Cronbachs alpha is most commonly used when you want to assess the internal consistency of a questionnaire or survey that is made up of multiple likerttype scales and items. Cronbach s alpha values are quite sensitive to the number of items in the scale. This article focuses on the introduction of theory and practice analyzing cronbachs alpha reliability. Using and interpreting cronbachs alpha university of virginia.
Spss reliability example portland state university. Alpha is a very nice command used to calculate cronbach s alpha for scales. Java project tutorial make login and register form step by step using netbeans and mysql database duration. Hasil korelasi pernyataan 125 dengan jumlah skor variabel pada kolom corrected itemtotal correlation sebesar 0,353 dan seterusnya, nilai reliabilitas alpha terletak pada tabel reliability statistic kolom cronbach alpha sebesar 0,751. If so, how will i compute it taking into consideration the varying levels of response options. Pada postingan kali ini saya akan berbagi cara melakukan uji reliabilitas alpha cronbach s dengan program spss. Cronbachs coefficient alpha provides an indication of the average correlation among all of the items that make up the scale. So this student judges the task value of cronbach s alpha to be important, or, more precisely, the average of this students ratings on these three items falls between a rating of 4 to a considerable degree and a rating of 5 to a great degree. Cronbach s alpha cronbach s alpha a is a measure of internal consistency, that is, how closely related a set of items are as a group.
Reliability statistics cronbach s alpha cronbach s alpha based on standardized items n of items. Internal consistency reliability for this study was measured in a variety of ways. After you finish data entry your spss screen should look something like figure 1 below. Listwise deletion based on all variables in the procedure. Cronbachs alpha is computed by correlating the score for each scale item with. Using and interpreting cronbachs alpha university of. This manual version shows the typical bell shaped normal distribution. Cronbachs alpha in this tutorial you will learn how to produce a simple and commonly used measure of reliability. Exploratory factor analysis and reliability analysis with.
Complete stats course in less than 60 minutes dr anna morganthomas reliability test. Does anyone have experience calculating ordinal alpha. Analysis cronbachs alpha reliability in spss spss expert. It is most commonly used when you have multiple likert questions in a surveyquestionnaire that form a scale and you wish to determine if the scale is reliable. It is just a statistical guide for quick decisions on reliability measures. Some days ago came to me a student who asked me a question about why spss calculates different alfa cronbach s for standardized and undstandardized data. In spss, how do i compute cronbachs alpha statistic to test. The basic syntax is simply alpha variables in the scale and requires at least two items. The results obtained in this study indicate the instrument has a very high level of validity as well as reliability. Fortunately, chad marshall wrote a wonderful introduction to cronbach s alpha, below. Spss manuals on cd, featuring manuals in pdf format for spss base and all.
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