Cronbach s alpha in this tutorial you will learn how to produce a simple and commonly used measure of reliability. 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. The second table of reliability statisticsis the table of interest, it gives the value of the cronbachs alpha and the number of items selected for the scale. In addition to an example of how to use a chisquare test, the window also identifies the sample data file you can use to follow the example for yourself. Reliability testing will be performed at several levels. For now, to illustrate how to access the spss tutorial, we will assume that. How to test validity questionnaire using spss the validity and reliability the instrument is essential in research data collection.
Ibm spss statistics 21 brief guide university of sussex. In analyzing the data, you want to ensure that these questions q1 through q5 all reliably measure the same latent variable i. How to do statistical analysis for test test reliability of a. Spss, standing for statistical package for the social sciences, is a powerful. How to test reliability method alpha using spss instruments are valid and reliable research is a necessary condition to obtain highquality research results. In spss, how do i compute cronbachs alpha statistic to test reliability. 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. This file shows the scores for 12 subjects taken two weeks apart to estimate test retest reliability, which is a measure of stability. At the end of these seven steps, we show you how to interpret the results from your cronbachs alpha analysis. Lets first navigate to analyze correlate bivariate as shown below. How to test reliability method alpha using spss spss tests. Listwise deletion based on all variables in the procedure. The ibm spss statistics 21 brief guide provides a set of tutorials designed to acquaint you with the various components of ibm spss statistics.
Cronbachs alpha in spss statistics procedure, output and. This recommends that the scale is consistent and highly reliable. Cronbachs alpha is most commonly used when you want to assess the internal consistency of a questionnaire or survey that is. Cronbachs alpha is the most common measure of internal consistency reliability. This statistics preparation material will cover the important concepts of statistics syllabus. Reliability analysis allows you to study the properties of measurement scales and the. For our scale of training needs analysiscronbachs alpha value reported to be 0. In spss, how do i compute cronbachs alpha statistic to test. A researcher developed a 9 question questionnaire to determine how safe people feel at their work. Cronbach alpha is a reliability test conducted within spss in order to measure the internal consistency i. After the research instrument is declared invalid in the validity of the test, then the next step i will give an example of reliability test method alpha method using spss.
In spss, how do i compute cronbachs alpha statistic to. A score of 90 on an invalid or unreliable test would be no different from a score of 50. Alternately, you can learn about our enhanced data setup content on our features. Click twotailed or onetailed, depending on your desired significance test. Remember also that i said we should conduct reliability analysis on any subscales individually.
Notice that you can scroll up to the previous output you created using the menu commands. How to use spsscronbachs alpha reliability test youtube. Hallgren correspondence concerning this article should be addressed to kevin hallgren, department of psychology, 1 university of new mexico, msc03 2220, albuquerque, nm 871. The examples include howto instructions for spss software. Simply put, a reliable measuring instrument is one which gives you the same measurements when you repeatedly measure the same unchanged objects or events. The pearson correlation is the testretest reliability coefficient, the sig. Mean i want to check the cronbach alpha of each variable in my research. How to test validity questionnaire using spss spss tests. This bias can be potentially avoided if the independent and dependent variables are measured at different points in time, using a longitudinal. This yields two scores for each person and the correlation between these two. To the discharge of testretest users, it must be acknowledged that correct methods for agreement, such as blandaltmans plot or the concordance correlation coefficient, are still not yet directly available in standard commercial statistical packages, such as sas, stata, and spss.
Various other statistical tools and tests used for analysis included reliability analysis, reliability testing, cronbachs alpha, kaisermeyerolkin measure of. This time, however, you cre ated the output by running the syntax code you created with the paste func tion. Click the options button, and check variance under. We saw that this holds for only 149 of our 388 cases. The measurements could be from two people or two types of equipment, or the same person on. Interitem correlation matrix se1 on the whole, i am satisfied with myself. Under the cronbachs alpha if item deleted the reliability of 0. Hallgren university of new mexico many research designs require the assessment of interrater reliability irr to. Reliability analysis allows you to study the properties of measurement scales and the items that compose the scales. 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. The commands should work with earlier versions of spss back to version 7. In this video we demonstrate how to run a independent sample ttest for a mean and a paired sample ttest for a mean. To run a paired samples t test in spss, click analyze compare means pairedsamples t test.
If you would like to know more about the characteristics of cohens kappa, including the null and alternative hypothesis it is testing, see our enhanced cohens kappa guide. The data file should have the two scores on the same line for each subject as shown in this screen. The hypotheses have been formulated and tested using spss software and the results have been arrived at. While writing this book we have used the spss base, advanced models, regression models,and the spss exact testsaddon modules. Descriptive and inferential statistics 4 the department of statistics and data sciences, the university of texas at austin click on the arrow button that will move those variables to the variables box. In the section, test procedure in spss statistics, we show you how to analyse your data using cohens kappa in spss statistics. Reliability analysis dialogue box for cronbachs alpha in spss statistics. We follow the spss convention of doing this to make clear which parts of the syntax are spss commands, subcommands or keywords, and which parts are variable names shown in lower case letters.
The calculation of testretest reliability is straightforward. The pearson correlation is the test retest reliability coefficient, the sig. If you are confused about how to open spss, ask your instructor or see appendix 1, where we provide more information about accessing spss from your hard drive or from a network. Saving an spss for windows 7 file once you have entered some data you should save the file. Spss factor can add factor scores to your data but this is often a bad idea for 2 reasons. This guide is intended for use with all operating system versions of the software, including. How to do statistical analysis for test test reliability. Reliability analysis on spss lets test the reliability of the saq using the data in saq. For example, for variables of type numeric, the default measurement scale is a continuous or interval scale referred to by spss as scale.
Spss statistics is a statistics and data analysis program for businesses, governments, research institutes, and academic organizations. To obtain descriptive statistics, such as mean, variance, skew, and kurtosis. Move all relevant variables into the variables box. It is good practice to save data at regular intervals during data entry just in case. The same test is administrated on two occasions to the same individuals under the same conditions. Reliability statistics cronbachs alpha cronbachs alpha based on standardized items n of items. There are multiple types of correlation coefficients. Find a technical tutorial in ibm developer find a best practice for integrating. These spss statistics tutorials briefly explain the use and interpretation of standard statistical analysis techniques for medical, pharmaceutical, clinical trials, marketing or scientific research. This is the first in a series of eight videos that will introduce. So these are the basics regarding cronbach alpha reliability tests and how to conduct them on spss. Information here may no longer be accurate, and links may no longer be available or reliable. Other available addon modules spss tables, spss categories, spss trends, spss.
Selecting pearson will produce the test statistics for a bivariate pearson correlation. The reliability analysis procedure calculates a number of commonly used measures of scale reliability and also provides information about the relationships between individual items in the scale. Nov 30, 2017 how to use spss are you ready to learn how to use spss for your introductory statistics class. In analyzing the data, you want to ensure that these. Now when you enter the response for item 4 into spss, you need to reverse the entry, for instance if the respondent has said 5, you will enter 1 into spss, similarly 4 will be exchange with 2 and vice versa. You probably dont want to change anything else here. Spss opens the draft output window with the same chart you created using the menu commands. Spss now opens the tutorial to the chisquare topic in the form of an internet page. Using spss to understand research and data analysis. In contrast to the standards in basic research, in many applied settings a reliability of. Reliability test method alpha method using spss how to test reliability. Suppose you wish to give a survey that measures job motivation by asking five questions. Bartletts test of sphericity tests the hypothesis that your correlation matrix is an identity matrix, which would indicate that your variables are unrelated and therefore unsuitable for structure detection. This content has been archived, and is no longer maintained by indiana university.
In this section, we set out this 7step procedure depending on whether you have version 26 or the subscription version of spss statistics or version 25 or earlier. Reliability test in spss using cronbach alpha project guru. Coefficient alpha and the internal structure of tests original paper from lee j. In case you would like to know more indepth, here are some additional sources i would suggest. Sep 24, 2012 determine the ability of a series of questions to measure the same construct or characteristictrait. The pairedsamples t test window opens where you will specify the variables to be used in the analysis. All of the variables in your dataset appear in the list on the left side.
For variables of type string, the default is a nominal scale. Cronbachs alpha can be carried out in spss statistics using the reliability analysis. Md aktaruzzaman assistant professor, iut, gazipur, bangladesh phd student, monash uni, melbourne, australia. It contains chapters discussing all the basic concepts of statistics with suitable examples. Tutorials in quantitative methods for psychology 2012, vol. Originally developed as a programming language for conducting statistical analysis, it has grown into a complex and powerful application. Focusing on exploratory factor analysis an gie yong and sean pearce university of ottawa the following paper discusses exploratory factor analysis and gives an overview of the statistical technique and how it is used in various research designs and applications. Mar 14, 2020 reliability testing is one of the key to better software quality. If an instrument lacks validity or reliability, the meaning of individual scores becomes otiose. Try ibm spss statistics subscription make it easier to perform powerful. However, it should be noted by the researcher that the test retest type of reliability analysis involves the correlated data between the observations which do not pose a statistical problem in assessing the reliability.
The example here is based on a fictional study that aims to examine students motivations to. Home basics spss popular tutorials spss factor analysis beginners tutorial what is factor analysis. Both test retest and interrater reliability are indexed with a productmoment correlation. Cronbachs alpha in this tutorial you will learn how to produce a simple and commonly used measure of reliability. To save the data you have just entered, click the file at the top left corner of the screen and then the save as.
We shall briefly discuss here methods of estimating an instruments reliability. Factor scores will only be added for cases without missing values on any of the input variables. Although commands are show in all caps, this is not necessary. Reliability is a measure to indicate that a reliable instrument to be used as a means of collecting data for the instrument is considered good. The main purpose of reliability testing is to check whether the software meets the requirement of customers reliability.
Calculating total scale scores and reliability spss. Computing interrater reliability for observational data. To test the internal consistency, you can run the cronbachs alpha test using the reliability command in spss, as follows. Cronbachs alpha in spss statistics procedure, output. The default chosen by spss depends on the data type. In this course, barton poulson takes a practical, visual, and nonmathematical approach to spss statistics, explaining how to use the popular program to analyze data in ways that are difficult or impossible in spreadsheets, but which dont require you to. Method alpha using spss tutorial reliability test with spss software complete. Determine the ability of a series of questions to measure the same construct or characteristictrait. 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. This testing helps discover many problems in the software design and functionality. In some cases, thirdparty developed functions are available.
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. Therefore, the correct data will be determining true the results of research quality. Spss stepbystep 5 1 spss stepbystep introduction spss statistical package for the social sc iences has now been in development for more than thirty years. Pearson correlation spss tutorials libguides at kent. Reliability spss output itemtotal statistics degree to which item correlates with the total score the reliability if the particular item is removed itemtotal statistics scale mean if item deleted scale variance. I am trying to find out test retest reliability of a questionnaire which measures on nominal scale. It is assumed that the errors are uncorrelated to each other. Now, you should have reverse scored item 3 see above. The total analysis was carried out by using spss 18.
1353 24 1389 14 1315 537 888 1061 431 765 122 1203 832 310 1163 1050 1031 624 1328 384 223 834 466 791 1143 736 59 44 1090 275 1188 1241 170 35 403