CODEWITHSUNDEEP
spss
Mustard
Mustard

Reputation: 33

General Linear Model - Repeated Measures with Covariates, Estimated Marginal Means are not adjusting? Bug?

I am running a Repeated Measures two-way ANCOVA. The model produces an Estimated Marginal Means table, but the values are exactly the same (to the hundredths decimal place) as the Means in the descriptive statistics, despite there being a note at the bottom of the EMM table indicating that "the covariates appearing in the model are evaluated at the following values:..."

Is this a bug, or could I be doing something wrong?

Descriptive Statistics Output

Estimate Marginal Means Output

Update:

Responding to question below, I should note that I used the drop down menus to run the analysis; however, this is the code that is used when I 'paste' the code.

DATASET ACTIVATE DataSet1.
GLM FT10 FT11 FT12 FT13 FT14 FT15 FT16 FT17 FT18 FT19 FT110 FT111 FT20 FT21 FT22 FT23 FT24 FT25 FT26 FT27 FT28 FT29 FT210 FT211 WITH SpatialScore FPSRTScore LDMean VGTotal
  /WSFACTOR=Matching 2 Polynomial Trial 12 Polynomial 
  /METHOD=SSTYPE(3)
  /PLOT=PROFILE(Trial*Matching) TYPE=LINE ERRORBAR=CI MEANREFERENCE=NO AXIS=AUTO
  /EMMEANS=TABLES(OVERALL) WITH(SpatialScore=MEAN FPSRTScore=MEAN LDMean=MEAN VGTotal=MEAN)
  /EMMEANS=TABLES(Matching) WITH(SpatialScore=MEAN FPSRTScore=MEAN LDMean=MEAN VGTotal=MEAN)COMPARE ADJ(BONFERRONI)
  /EMMEANS=TABLES(Trial) WITH(SpatialScore=MEAN FPSRTScore=MEAN LDMean=MEAN VGTotal=MEAN)COMPARE ADJ(BONFERRONI)
  /EMMEANS=TABLES(Matching*Trial) WITH(SpatialScore=MEAN FPSRTScore=MEAN LDMean=MEAN VGTotal=MEAN)
  /PRINT=DESCRIPTIVE ETASQ 
  /CRITERIA=ALPHA(.05)
  /WSDESIGN=Matching Trial Matching*Trial
  /DESIGN=SpatialScore FPSRTScore LDMean VGTotal.

Upvotes: 1

Views: 224

Answers (1)

David Nichols
David Nichols

Reputation: 586

This is expected behavior. The reason that the EMMEANS don't differ from the observed means is that the covariate adjustment is done at the cell level in terms of between-subjects effects, and you have only one cell because you don't have any between-subjects factors.

Upvotes: 0

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