My Cronbach Alpha stated -0.656. The note below says: The value is negative due to a negative average covariance among items. This violates reliability model assumptions. You may want to check item codings.
What does this mean?
You may look at:
http://spssx-discussion.1045642.n5.nabble.com/Negative-Covariance-and-Reliability-Analysis-td1073862.html
You may look at:
http://spssx-discussion.1045642.n5.nabble.com/Negative-Covariance-and-Reliability-Analysis-td1073862.html
Dear @Fatimah, the following link discusses the issue of reliability Statistics:
https://explorable.com/statistical-reliability
This notification says your data cannot be use for any scientific conclusion because some of your variables are coded incorrectly.
You must check them one by one and correct or recode them.
I am not an expert in SPSS. However, If you type your question in google. You will see that this question has been asked frequently. I have attached the links which you may find useful:
https://www.google.com/#q=his+violates+reliability+model+assumptions.+You+may+want+to+check+item+codes&spell=1
https://www.mail-archive.com/[email protected]/msg07205.html
http://www.talkstats.com/showthread.php/1687-Cronbach-Alpha-reliability
https://groups.google.com/forum/#!topic/comp.soft-sys.stat.spss/IVp-wCTSxR8
Another solution is to switch of row and column calculation on the panel of statistics....your alfa will turn on positive :)
Dear all, thank you for your responses. I've found the culprit, as Agnes mentioned, I must transposed the variables. My ICC is now 0.827 :) ;) - 82.7% is real.
Dear Fatimah, im new on SPSS and i encounter the same problem also. Can you explain more on how to rectify the mistake. Thanks
Hello Fatema
1. The Item alpha reliability is the average of the output of correlation coefficients.
2. The correlation coefficients of the questions i.e. the correlation between two or more corresponding variables/observations of the instrument are negative
3. The acceptable value should be >= 0.7.
4. As a measure of consistency of your questionnaires, you have a serious problem and needs to be observed.
5. The scales of measurement need to be checked and the consistency of the scale/survey need to be studied.
6. In order to discover the problems of your questionnaires, the measures of Item alpha reliability if item deleted and and split-half reliability need to be developed.
Regards,
Zuhair
In addition, in SPSS all the measures of reliability can be developed. Some of references are:
1. Landau, S. and Everitt, B. S.(2004). A Handbook of Statistical analyses using SPSS.
2. Howitt, D. and Cramer, D.(2008). Introduction to SPSS.
3. Z. A. Al-Hemyari and A. M. Al-Sarmi (2016). Validity and Reliability of Students and Academic Staff’s Surveys to Improve Higher Education. Educational Alternatives, Journal of International Scientific Publications, Vol.14, pp. 242-263.
4. If you want resources/guides for SPSS, I will supply.
Regards,
Zuhair
Please check out this link:
https://stats.idre.ucla.edu/spss/library/how-negative-reliability-coefficients-can-occur/
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