Reliability statistics cronbachs alpha cronbachs alpha based on standardized items n of items. A high alpha indicates that the separate items are correlated. Cronbach alpha is a reliability test conducted within spss in order to measure the internal consistency i. For more information on cronbachs alpha, see spss library. Introduction the pleasure writers experience in writing considerably in. 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. In reliability, the spss command for running a cronbachs alpha, the only options for missing data are to include or exclude userdefined missing data. Dalam program spss metode yang sering digunakan untuk uji reliabilitas adalah dengan menggunakan metode alpha cronbachs. Cronbachs alpha is the average value of the reliability coefficients one would obtained for all. Now that data are collected, we are interested in determining the cronbach s alpha for both scales, task value and anxiety. With these data now consider how one calculates in spss cronbach s alpha for both scales, task value and anxiety. Cronbach did not refer to this coefficient as alpha, nor did it recommend using it. Reliability is normally reported under the head of instrumentation in the methodology section.
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. However, the rules of thumb listed above should be used with caution. In spss, how do i compute cronbachs alpha statistic to. It is generally used as a measure of internal consistency or reliability of a psychometric instrument. For more information about intraclass coefficients as a measure of reliability, see spss library. Penjelasan uji reliabilitas instrumen lengkap uji statistik. Cronbachs alpha is designed to determine internal consistency of attitude scales. Pada postingan kali ini saya akan berbagi cara melakukan uji reliabilitas alpha cronbach s dengan program spss. This model is a model of internal consistency, based on the average interitem correlation. Calculating, interpreting, and reporting cronbachs alpha. Uji reliabilitas dalam hal ini mengacu pada nilai alpha yang terdapat dalam tabel output spss.
How to test reliability method alpha using spss instruments are valid and reliable research is a necessary condition to obtain highquality research results. Cronbachs alpha the most common measure of internal consistency reliability. Cronbachs alpha using spss introduction cronbachs alpha is the most common measure of internal consistency reliability. Using the alpha option, the corr procedure computes cronbachs coefficient alpha in output 2. 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 re. This article focuses on the introduction of theory and practice analyzing cronbachs alpha reliability. Below are stepbystep commands for calculating cronbach s alpha in spss. Conduct and interpret an internal consistency reliability analysis through cronbach s alpha, the corrected itemtotal correlations and the interitem correlation matrix. Cronbachs alpha gives us a simple way to measure whether or not a score is reliable. 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. It is most commonly used when the questionnaire is developed using multiple likert scale statements and therefore to determine if the scale is reliable or not. In other words, it measures how well a set of variables or items measures a single, onedimensional latent aspect of individuals. This model computes guttmans lower bounds for true reliability. Entering data in spss statistics the one person, one row rule.
Andy field page 4 2152006 finally, and perhaps most important, the value of alpha at the very bottom is the cronbachs alpha. Cronbach s alpha is the most common measure of internal consistency reliability. Alpha is a very nice command used to calculate cronbach s alpha for scales. After data entry the spss screen should look something like figure 1 below.
That is, does it look like the item measures what it is. Table 3 shows the itemanalysis output from spss for the multiitem scale of student. It is most commonly used when the questionnaire is developed using multiple likert scale statements and therefore to. Alpha is a very nice command used to calculate cronbachs alpha for scales. Since cronbachs alpha reliability is sensitive to the number of items in a scale. Listwise deletion based on all variables in the procedure. Calculating cronbachs alpha in spss improving internal. Questionnaire evaluation with factor analysis and cronbachs alpha an example melanie hof 1. Berikut cara melakukan uji reliabilitas spss terhadap data kuesioner. An exploratory factor analysis and reliability analysis of.
Conduct and interpret an internal consistency reliability analysis through cronbachs alpha, the corrected itemtotal correlations and the interitem correlation matrix. Using and interpreting cronbachs alpha university of. Cronbachs alpha coefficient increases either as the number of items variables increases, or as the average interitem correlations increase i. Cronbachs alpha if item deleted we can see that removal of any question, except question 8, would result in a lower cronbachs alpha. So the only way to include cases with more than 50% observed data would be to impute them in a separate step before you run the reliability analysis. Pengertian uji reliabilitas menurut sugiarto dan situnjuk 2006, uji reliabilitas reliability adalah pengujian yang menunjukkan apakah suatu instrumen yang digunakan untuk memperoleh. If the model is split, then the variables are divided into 2 subsets. If you dont have a dataset, you can download the example dataset here. How to use spsscronbachs alpha reliability test youtube. Uji dilakukan pada taraf signifikasi a sebesar 0,05. Cronbachs alpha in this tutorial you will learn how to produce a simple and commonly used measure of reliability. Analysis cronbachs alpha reliability in spss spss expert. Salah satu kelemahan perhitungan koefisien reliabilitas dengan menggunakan teknik belah dua adalah 1 banyaknya butir soal harus genap, dan 2 dapat dilakukan dengan cara yang berbeda sehingga menghasilkan nilai yang berbeda pula seperti terlihat pada contoh c.
An optional parameter n may be given, to specify how many variables to be in the first subset. 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. Items 1 and 2 are responded using a 6point likert scale. It is used under the assumption that you have multiple items measuring the same underlying construct. Fortunately, chad marshall wrote a wonderful introduction to cronbachs alpha, below. Cronbachs 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. Cronbach s alpha in this tutorial you will learn how to produce a simple and commonly used measure of reliability. Fortunately, chad marshall wrote a wonderful introduction to cronbach s alpha, below. Cara uji reliabilitas spss alpha cronbachs data kuesioner.
Tauequivalent reliability is a singleadministration reliability i. For validity you need to first look at face validity. Richardson purdue university abstract the purpose of this study was to develop an effective instrument to measure student readiness in online. Computing cronbachs alpha in spss with missing data the. Calculating total scale scores and reliability spss. 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. I am currently evaluating the validity and reliability of a scale. Chad marshall is currently a dba student in the mitchell college of business at the university of south alabama.
Calculating and interpreting cronbachs alpha using spss. An exploratory factor analysis and reliability analysis of the student online learning readiness solr instrument taeho yu university of virginia jennifer c. Cara melakukan uji reliabilitas alpha cronbachs dengan spss. 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.
You would have to calculate the alpha of each of the 8 each contstructs using i assume 5 items each, and one for the 5 items that will form your dependent variable. The basic syntax is simply alpha variables in the scale and requires at least two items. Now that data are collected, we are interested in determining the cronbachs alpha for both scales, task value and anxiety. Cronbach s alpha measures the internal consistency of scales that are made up of multiple items. Cronbach s alpha coefficient increases either as the number of items variables increases, or as the average interitem correlations increase i. This book is intended for those who want to learn the basics of spss. Cronbachs alpha is a measure used to assess the reliability, or internal consistency, of a set of scale or test items. Enter the data into spss as shown above in table 3. For more information about reading data in spss, see the spss command syntax reference. Is cronbachs alpha sufficient for assessing the reliability.
This video describes how to calculate and interpret cronbach s alpha using spss. Pada postingan kali ini saya akan berbagi cara melakukan uji reliabilitas alpha cronbachs dengan program spss. Sas and spss macros to calculate standardized cronbachs. Then there are a few options which can be used to finetune the command. Cronbachs alpha values are quite sensitive to the number of items in the scale. Cronbachs alpha is the most common measure of internal consistency reliability. Cronbachs alpha reliability analysis of measurement scales. If alpha is specified, then cronbachs alpha is calculated for the scale. Uji reliabilitas spss adalah pengujian yang mengukur tingkat konsisten atau kestabilan data kuesioner menggunakan software spss. First of all, the reverse variable list causes stata to reverse score. Cronbach s alpha reliability coefficient normally ranges between 0 and 1. Questionnaire evaluation with factor analysis and cronbach. In the dataset, we are investigating the relationship of job satisfaction and job performance, but we need to see whether our job satisfaction measure is internally consistent first.
Rumus uji reliabilitas teknik non belah dua non splithalf technique. Calculating, interpreting, and reporting cronbachs alpha reliability coefficient for likerttype scales joseph a. A case is the object which you are measuring in someway. The first important table is the reliability statistics table that provides the actual value for cronbachs alpha 8. In spss, how do i compute cronbachs alpha statistic to test. Cronbachs alpha in spss statistics procedure, output and. The cronbachs coefficient alpha is a lower bound for the reliability coefficient for the raw variables and the standardized variables. Calculating, interpreting, and reporting cronbach s alpha reliability coefficient for likerttype scales joseph a. Cronbach s alpha is the average value of the reliability coefficients one would obtained for all. Cronbach s alpha is designed to determine internal consistency of attitude scales.
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. The correlations between variables should be consistently high. 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. 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. Cronbach s alpha measurement of internal consistency. Cronbachs coefficient alpha provides an indication of the average correlation among all of the items that make up the scale. Cronbachs alpha measures the internal consistency of scales that are made up of multiple items. Generally, many quantities of interest in medicine, such as anxiety or degree. Each chapter has instructions that guide you through a series of problems, as well as graphics showing you what your. Below are stepbystep commands for calculating cronbachs alpha in spss.
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. It can be used as a text in a class or by those working independently. 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. Lowmotivated writers perform worse, since they spend less. Once you are familiar with cronbachs alpha, we can then use spss to calculate it. Spss statistics sets out its data in a spreadsheetlike manner. Questionnaire evaluation with factor analysis and cronbachs. My personal observation has been that when someone calculatures alpha for a mixture of scales like dichotomous, policychotomous, likert etc, then probability of alpha being negative or low is higher. If you need to learn more about cronbachs alpha, click here to read it.
The principle behind entering data in almost all cases in spss statistics is to enter each unique case on a new row. Cronbachs alpha is most commonly used when you want to assess the internal consistency of a questionnaire or survey that is. Calculating and interpreting cronbach s alpha using spss. In the assessment of the internal consistency of an instrument, the present study proposed the cronbachs alphas coefficient to be set at 0. Instrumen dapat dikatakan reliabel bila nilai cronbachs alpha lebih besar dari r tabel. Cronbachs alpha in spss statistics procedure, output. Cronbachs alpha reliability coefficient normally ranges between 0 and 1. So the conclusion, from my observation, may be personal or biased, is that the use consistent scales be used when calculating cronbach s alpha. After you finish data entry your spss screen should look something like figure 1 below.