Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

From |
"Carlo Lazzaro" <carlo.lazzaro@tin.it> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
st: R: Does there exist measurement error when I got high Cronbach's alpha? |

Date |
Sun, 17 Jul 2011 11:01:05 +0200 |

Sharon wrote: "Another question is about the computation of Cronbach's alpha. I got different values of alpha when using different computation procedure: the key difference happened when I recoded the responses of five factors personality to "missing values" when the original responses were "-3" (i.e. no questions answered) or "-2" (i.e. information incomplete)." As far as this portion of your message is concerned, I would recommend you to discover which kind of missing mechanism underlies your missing data. Missing data mechanism is probably the substantive topic and, missing data, the reason why you are faced with different values of Cronbach's alphas (or of whatever statistc you're interested in). I would figure out that you might have missing at random (MAR) or missing non at random (MNAR or NMAR)observations. Problems with managing missing data usually arise when they are MNAR. For further details on this topic, I take the liberty to refer you to the following references: Little RJA, Rubin DR. Statistical analysis with missing data. 2nd ed. Chichester: Wiley, 2002; Allison PD. Missing data. Thousand Oaks, CA: Sage Publications, 2002; Royston, P. 2004. Multiple imputation of missing values. Stata Journal 4(3): 227-241. Royston, P. 2005. Multiple imputation of missing values: update. Stata Journal 5(2): 1-14. Kindest Regards, Carlo -----Messaggio originale----- Da: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] Per conto di xueliansharon Inviato: sabato 16 luglio 2011 14.47 A: statalist@hsphsun2.harvard.edu Oggetto: st: Does there exist measurement error when I got high Cronbach's alpha? Dear all: I got quite high Cronbach's alphas (0.9) for five-factor personality traits (extraversion, agreeableness, conscientiousness, emotional stability and intellect). With such high values, can I argue that there may still exist measurement errors in the measures for five-factor personality traits? Another question is about the computation of Cronbach's alpha. I got different values of alpha when using different computation procedure: the key difference happened when I recoded the responses of five factors personality to "missing values" when the original responses were "-3" (i.e. no questions answered) or "-2" (i.e. information incomplete). For example, for the extraversion measure, the range of the score should be 5 to 50 points, when I recoded the response "-3" or "-2" to "missing value", the sample size was reduced by around 680, since the number of observations who didn't answer the questions about extraversion or didn't provide complete information for each item were 680, and the alpha coefficient fell from 0.9 to 0.6. So is it correct to do such recoding when computing alpha coefficients? Your response is greatly appreciated. Thanks & Regards, Sharon -- View this message in context: http://statalist.1588530.n2.nabble.com/Does-there-exist-measurement-error-wh en-I-got-high-Cronbach-s-alpha-tp6589508p6589508.html Sent from the Statalist mailing list archive at Nabble.com. * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**st: Does there exist measurement error when I got high Cronbach's alpha?***From:*xueliansharon <xuelianstata@gmail.com>

- Prev by Date:
**st: posting results after qreg** - Next by Date:
**st: How to store the pseudo r2 from quantile regression** - Previous by thread:
**Re: st: Does there exist measurement error when I got high Cronbach's alpha?** - Next by thread:
**Re: st: Does there exist measurement error when I got high Cronbach's alpha?** - Index(es):