CODEWITHSUNDEEP
regressionspssmissing-datafactor-analysis
ur_land
ur_land

Reputation: 9

How does SPSS assign factor scores for cases where underlying variables were pairwise deleted?

Here's a simplified example of what I'm trying to figure out from a report. All analyses are being run in SPSS, which I don't have and don't use (my experience is with SAS and R).

They were running a regression to predict overall meal satisfaction from food type ordered, self-reported food flavor, and self-reported food texture.

But food flavor and texture are highly correlated, so they conducted a factor analysis, found food flavor and texture load on one factor, and used the factor scores in the regression.

However, about 40% of respondents don't have responses on self-reported food texture, so they used pairwise deletion while making the factors.

My question is when SPSS calculates the factor scores and outputs them as new variables in the data set, what does it do with people who had an input for a factor that was pairwise deleted?

How does it calculate (if it calculates it at all) factor scores for those people who had a response pairwise deleted during the creation of the factors and who therefore have missing data for one of the variables?

Upvotes: 0

Views: 202

Answers (1)

alexwhitworth
alexwhitworth

Reputation: 4907

Factor scores are a linear combination of their scaled inputs. That is, given normalized variables X1, ..., Xn, we have the following (where LaTeX formatting isn't supported and the L's indicate the loadings)

f = \sum_{i=1}^n L_i X_i

In your case n = 2. Now suppose one of the X_i is missing. How do you take a sum involving a missing value? Clearly, you cannot... unless you impute it.

I don't know what the analyst who created your report did. I suggest you ask them.

Upvotes: 0

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