Steven Stoline
2017-Feb-21 15:43 UTC
[R] Correlations Table of Items when compute Cronbach's Alpha
Dear All: I am using *alpha(data, **check.keys=TRUE) or alpha(data, keys = c(1, 1, 1, -1))* to compute the Cronbach's Alpha. I am using *check.keys=TRUE* or *keys = c(1, 1, 1, -1) *to automatically reverse items. *My question is: *how can I get the correlation tables (matrix) of the reversed items as part of the R output. *Here is an example of the data set:* X1 X2 X3 X4 2 5 4 4 1 1 1 6 1 2 1 6 2 3 2 4 1 2 1 6 1 3 1 6 2 2 2 5 2 1 1 6 2 2 4 5 5 5 2 1 1 3 1 6 1 1 1 6 1 1 1 6 2 2 2 5 2 2 2 2 1 6 1 6 1 2 1 6 2 2 3 5 2 5 4 5 2 1 2 6 2 2 1 5 2 2 2 6 1 1 1 6 1 1 1 6 1 1 1 5 1 2 2 5 2 2 2 5 1 2 2 5 1 4 2 5 2 2 2 2 2 2 4 5 2 1 2 5 2 2 2 5 2 2 2 5 2 2 2 5 2 2 2 5 5 2 2 5 2 2 1 5 2 5 6 2 2 4 2 5 2 2 2 4 2 3 5 1 3 3 3 6 2 2 2 4 2 2 2 5 2 2 2 5 1 1 1 6 1 1 1 5 6 1 1 6 1 1 1 6 2 6 4 3 1 1 1 6 1 1 1 6 4 5 5 5 5 2 2 5 2 2 2 5 1 2 1 6 1 5 1 6 1 4 2 5 2 1 1 5 4 2 1 5 2 2 2 5 1 1 1 6 6 1 1 4 1 2 1 6 1 1 1 5 1 1 1 6 1 4 1 3 1 1 1 6 5 2 2 5 2 2 2 5 1 1 1 6 1 1 1 5 4 4 2 4 3 2 2 5 1 2 1 6 1 2 1 6 2 1 1 5 2 6 1 6 4 3 1 5 1 1 1 5 1 1 1 6 4 5 4 5 1 1 1 2 1 1 1 6 1 1 1 6 4 4 3 4 2 2 2 4 1 2 2 4 1 1 1 6 2 3 2 5 2 6 NA 5 2 2 2 5 1 2 3 4 2 1 2 5 1 2 2 6 1 1 2 6 1 2 2 5 2 2 2 5 1 5 5 2 1 2 1 5 1 5 2 4 2 4 1 6 6 1 1 2 2 2 2 5 1 1 1 6 1 1 1 2 2 2 2 4 1 1 1 6 4 2 2 5 2 3 1 5 2 1 2 5 2 2 1 5 1 2 2 5 1 2 1 5 6 2 2 4 2 2 5 2 2 5 3 5 1 4 4 4 1 1 1 6 thank you steve ------------------------ Steven M. Stoline sstoline at gmail.com [[alternative HTML version deleted]]
Mark Sharp
2017-Feb-21 17:13 UTC
[R] Correlations Table of Items when compute Cronbach's Alpha
Have you looked at the help page? ?alpha::alpha See the section labeled Value. Look at output <- alpha(data, keys = c(1, 1, 1, -1)) output$r output$r.cor output$r.drop R. Mark Sharp, Ph.D. msharp at TxBiomed.org> On Feb 21, 2017, at 9:43 AM, Steven Stoline <sstoline at gmail.com> wrote: > > Dear All: > > > I am using *alpha(data, **check.keys=TRUE) or alpha(data, keys = c(1, 1, > 1, -1))* to compute the Cronbach's Alpha. I am using *check.keys=TRUE* > or *keys = c(1, 1, 1, -1) *to automatically reverse items. > > > *My question is: *how can I get the correlation tables (matrix) of the > reversed items as part of the R output. > > > > *Here is an example of the data set:* > > > X1 X2 X3 X4 > 2 5 4 4 > 1 1 1 6 > 1 2 1 6 > 2 3 2 4 > 1 2 1 6 > 1 3 1 6 > 2 2 2 5 > 2 1 1 6 > 2 2 4 5 > 5 5 2 1 > 1 3 1 6 > 1 1 1 6 > 1 1 1 6 > 2 2 2 5 > 2 2 2 2 > 1 6 1 6 > 1 2 1 6 > 2 2 3 5 > 2 5 4 5 > 2 1 2 6 > 2 2 1 5 > 2 2 2 6 > 1 1 1 6 > 1 1 1 6 > 1 1 1 5 > 1 2 2 5 > 2 2 2 5 > 1 2 2 5 > 1 4 2 5 > 2 2 2 2 > 2 2 4 5 > 2 1 2 5 > 2 2 2 5 > 2 2 2 5 > 2 2 2 5 > 2 2 2 5 > 5 2 2 5 > 2 2 1 5 > 2 5 6 2 > 2 4 2 5 > 2 2 2 4 > 2 3 5 1 > 3 3 3 6 > 2 2 2 4 > 2 2 2 5 > 2 2 2 5 > 1 1 1 6 > 1 1 1 5 > 6 1 1 6 > 1 1 1 6 > 2 6 4 3 > 1 1 1 6 > 1 1 1 6 > 4 5 5 5 > 5 2 2 5 > 2 2 2 5 > 1 2 1 6 > 1 5 1 6 > 1 4 2 5 > 2 1 1 5 > 4 2 1 5 > 2 2 2 5 > 1 1 1 6 > 6 1 1 4 > 1 2 1 6 > 1 1 1 5 > 1 1 1 6 > 1 4 1 3 > 1 1 1 6 > 5 2 2 5 > 2 2 2 5 > 1 1 1 6 > 1 1 1 5 > 4 4 2 4 > 3 2 2 5 > 1 2 1 6 > 1 2 1 6 > 2 1 1 5 > 2 6 1 6 > 4 3 1 5 > 1 1 1 5 > 1 1 1 6 > 4 5 4 5 > 1 1 1 2 > 1 1 1 6 > 1 1 1 6 > 4 4 3 4 > 2 2 2 4 > 1 2 2 4 > 1 1 1 6 > 2 3 2 5 > 2 6 NA 5 > 2 2 2 5 > 1 2 3 4 > 2 1 2 5 > 1 2 2 6 > 1 1 2 6 > 1 2 2 5 > 2 2 2 5 > 1 5 5 2 > 1 2 1 5 > 1 5 2 4 > 2 4 1 6 > 6 1 1 2 > 2 2 2 5 > 1 1 1 6 > 1 1 1 2 > 2 2 2 4 > 1 1 1 6 > 4 2 2 5 > 2 3 1 5 > 2 1 2 5 > 2 2 1 5 > 1 2 2 5 > 1 2 1 5 > 6 2 2 4 > 2 2 5 2 > 2 5 3 5 > 1 4 4 4 > 1 1 1 6 > > > thank you > steve > > ------------------------ > Steven M. Stoline > sstoline at gmail.com > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.CONFIDENTIALITY NOTICE: This e-mail and any files and/or...{{dropped:10}}
David L Carlson
2017-Feb-21 17:44 UTC
[R] Correlations Table of Items when compute Cronbach's Alpha
Actually you will need ?psych::alpha to get the help page. The correlations provided in output$item.stats are with the total score. If you want a correlation matrix for the original 4 variables you can use sweep() to invert the necessary column(s):> cor(sweep(dat, 2, c(1, 1, 1, -1), FUN="*"), use="complete.obs")X1 X2 X3 X4 X1 1.0000000 0.1396653 0.1916540 0.2865590 X2 0.1396653 1.0000000 0.5184912 0.2938423 X3 0.1916540 0.5184912 1.0000000 0.5037861 X4 0.2865590 0.2938423 0.5037861 1.0000000 If you use check.keys=TRUE you can extract the vector from the results:> output <- alpha(dat, check.keys=TRUE)Warning message: In alpha(dat, check.keys = TRUE) : Some items were negatively correlated with total scale and were automatically reversed. This is indicated by a negative sign for the variable name.> output$keys[1] 1 1 1 -1 ------------------------------------- David L Carlson Department of Anthropology Texas A&M University College Station, TX 77840-4352 -----Original Message----- From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Mark Sharp Sent: Tuesday, February 21, 2017 11:14 AM To: Steven Stoline <sstoline at gmail.com> Cc: r-help at r-project.org Subject: Re: [R] Correlations Table of Items when compute Cronbach's Alpha Have you looked at the help page? ?alpha::alpha See the section labeled Value. Look at output <- alpha(data, keys = c(1, 1, 1, -1)) output$r output$r.cor output$r.drop R. Mark Sharp, Ph.D. msharp at TxBiomed.org> On Feb 21, 2017, at 9:43 AM, Steven Stoline <sstoline at gmail.com> wrote: > > Dear All: > > > I am using *alpha(data, **check.keys=TRUE) or alpha(data, keys = c(1, 1, > 1, -1))* to compute the Cronbach's Alpha. I am using *check.keys=TRUE* > or *keys = c(1, 1, 1, -1) *to automatically reverse items. > > > *My question is: *how can I get the correlation tables (matrix) of the > reversed items as part of the R output. > > > > *Here is an example of the data set:* > > > X1 X2 X3 X4 > 2 5 4 4 > 1 1 1 6 > 1 2 1 6 > 2 3 2 4 > 1 2 1 6 > 1 3 1 6 > 2 2 2 5 > 2 1 1 6 > 2 2 4 5 > 5 5 2 1 > 1 3 1 6 > 1 1 1 6 > 1 1 1 6 > 2 2 2 5 > 2 2 2 2 > 1 6 1 6 > 1 2 1 6 > 2 2 3 5 > 2 5 4 5 > 2 1 2 6 > 2 2 1 5 > 2 2 2 6 > 1 1 1 6 > 1 1 1 6 > 1 1 1 5 > 1 2 2 5 > 2 2 2 5 > 1 2 2 5 > 1 4 2 5 > 2 2 2 2 > 2 2 4 5 > 2 1 2 5 > 2 2 2 5 > 2 2 2 5 > 2 2 2 5 > 2 2 2 5 > 5 2 2 5 > 2 2 1 5 > 2 5 6 2 > 2 4 2 5 > 2 2 2 4 > 2 3 5 1 > 3 3 3 6 > 2 2 2 4 > 2 2 2 5 > 2 2 2 5 > 1 1 1 6 > 1 1 1 5 > 6 1 1 6 > 1 1 1 6 > 2 6 4 3 > 1 1 1 6 > 1 1 1 6 > 4 5 5 5 > 5 2 2 5 > 2 2 2 5 > 1 2 1 6 > 1 5 1 6 > 1 4 2 5 > 2 1 1 5 > 4 2 1 5 > 2 2 2 5 > 1 1 1 6 > 6 1 1 4 > 1 2 1 6 > 1 1 1 5 > 1 1 1 6 > 1 4 1 3 > 1 1 1 6 > 5 2 2 5 > 2 2 2 5 > 1 1 1 6 > 1 1 1 5 > 4 4 2 4 > 3 2 2 5 > 1 2 1 6 > 1 2 1 6 > 2 1 1 5 > 2 6 1 6 > 4 3 1 5 > 1 1 1 5 > 1 1 1 6 > 4 5 4 5 > 1 1 1 2 > 1 1 1 6 > 1 1 1 6 > 4 4 3 4 > 2 2 2 4 > 1 2 2 4 > 1 1 1 6 > 2 3 2 5 > 2 6 NA 5 > 2 2 2 5 > 1 2 3 4 > 2 1 2 5 > 1 2 2 6 > 1 1 2 6 > 1 2 2 5 > 2 2 2 5 > 1 5 5 2 > 1 2 1 5 > 1 5 2 4 > 2 4 1 6 > 6 1 1 2 > 2 2 2 5 > 1 1 1 6 > 1 1 1 2 > 2 2 2 4 > 1 1 1 6 > 4 2 2 5 > 2 3 1 5 > 2 1 2 5 > 2 2 1 5 > 1 2 2 5 > 1 2 1 5 > 6 2 2 4 > 2 2 5 2 > 2 5 3 5 > 1 4 4 4 > 1 1 1 6 > > > thank you > steve > > ------------------------ > Steven M. Stoline > sstoline at gmail.com > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.CONFIDENTIALITY NOTICE: This e-mail and any files and/or...{{dropped:9}}