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From |
"David Radwin" <dradwin@mprinc.com> |

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

Subject |
st: RE: Mean test in a Likert Scale |

Date |
Thu, 30 Aug 2012 16:13:22 -0700 (PDT) |

Leonor, No, you can't correctly calculate the mean of an ordinal-level measure like the Likert scale you describe, although plenty of people do it anyway. But you can use -ttest- with these data if you first collapse each variable to a dichotomous (dummy) variable, because the mean of a dichotomous variable is identical to the proportion where the value is 1. As a guess, you might set the highest two values to 1, the lowest two values to 0, and the middle value to missing to calculate the proportion agreeing or somewhat agreeing. David -- David Radwin Senior Research Associate MPR Associates, Inc. 2150 Shattuck Ave., Suite 800 Berkeley, CA 94704 Phone: 510-849-4942 Fax: 510-849-0794 www.mprinc.com > -----Original Message----- > From: owner-statalist@hsphsun2.harvard.edu [mailto:owner- > statalist@hsphsun2.harvard.edu] On Behalf Of Leonor Saravia > Sent: Thursday, August 30, 2012 3:23 PM > To: statalist@hsphsun2.harvard.edu > Subject: st: Mean test in a Likert Scale > > Hello, > > I'm working with a survey that presents 26 questions and each of them > has as possible answer a 5 point Likert scale from Desagree (1) to > Agree (5). This survey was applyed for a treatment and a control > group. > > As far as I know, it is possible to analyze the information given only > by the proportions of each answer; for instance, 25% agrees, 50% > desagree, or so. > > I have two questions that maybe one of you have had before: > > a) Is it possible to calculate the mean score of a sample (treatment > or control group) - adding the individual answers - when one is > working with a Likert scale? > > b) If it is possible to calculate a mean score of a sample when using > a Likert scale, to compare the answers of the treatment versus the > control group, is it well done if I use the 'ttest' command? > > > Thank you in advance. > > Best regards, > > Leonor * * 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/

**Follow-Ups**:**Re: st: RE: Mean test in a Likert Scale***From:*Nick Cox <njcoxstata@gmail.com>

**References**:**st: Mean test in a Likert Scale***From:*Leonor Saravia <lmisaravia@gmail.com>

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