Factor analysis is not great with binary data. It tends to pick up factors corresponding to variable if similar popularity, rather than conceptual coherence. Also varimax rotation tends to pile to much variance up on the first factor. Try equimax for a more even spread.
Best, Chris ----- Christopher D. Green Department of Psychology York University Toronto, ON M6C 1G4 Canada [email protected] On Jun 18, 2013, at 3:31 PM, Annette Taylor <[email protected]> wrote: > I am coming to the statistical well one more time. Sigh. > > Other than what I can figure out from SPSS with my colleague, we are at a > loss on what we can do with factor analysis--we understand the basic > premises. The problem is how to carry it out with SPSS. Or perhaps we have > done it correctly and there truly is nothing here :( We had hoped to find > some factors and had a couple of possible ways we thought the items might > cluster together. > > We have a data set with over 200 participants and a questionnaire with 23 > items. > > The items were coded as 0 = incorrect response and 1 = correct response in a > 2-choice forced-choice format. > > We entered the 0,1 data set for these participants into a factor analysis > using principal components analysis with a varimax rotation method with > Kaiser normalization that gives what we understand to be an "orthogonal" > analysis. > > We have 10 factors for the 23 items, the largest has 5 items, then there a > bunch of 3, 2, 1 item factors :( > > We repeated this with a principal components analysis with a quatrimax > rotation with Kaiser normalization which gave us what we think is a > "correlated" analysis. > > Except for the precise component values the factors were 100% exactly the > same. > > Unfortunately, the factors seem weird to us and not at all what we might have > predicted in our scenario. > > Does someone with more factor analysis knowledge have some suggestions for us? > > Thanks in advance! > > Annette > > > > Annette Kujawski Taylor, Ph. D. > Professor, Psychological Sciences > University of San Diego > 5998 Alcala Park > San Diego, CA 92110 > [email protected] > --- > You are currently subscribed to tips as: [email protected]. > To unsubscribe click here: > http://fsulist.frostburg.edu/u?id=430248.781165b5ef80a3cd2b14721caf62bd92&n=T&l=tips&o=26137 > or send a blank email to > leave-26137-430248.781165b5ef80a3cd2b14721caf62b...@fsulist.frostburg.edu > --- You are currently subscribed to tips as: [email protected]. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5&n=T&l=tips&o=26145 or send a blank email to leave-26145-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
