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rjinks
Obsidian | Level 7

I have output values for my maximum likelihood analysis that are 1.00 and I have an error message that correlation matrix is singular. Where or what is the cause of these these 2 issues?

Datalines;
LC 0 0 0.024266667 0.015533333 0.02602 0.008633333 0.010333333 0.017233333 0 0.006366667 0.041333333 0.016933333 0.023333333 0.053833333
SK1 0.004966667 0.004966667 0.0078 0.005666667 0.008533333 0 0 0.0078 0 0 0.003566667 0.003566667 0.008593333 0.027133333
WR1 0.0042 0.0077 0.04 0.0175 0.02539 0.0063 0.0091 0.0224 0 0 0 0.0091 0.018216667 0.093156667
WR2 0 0 0.00595 0.00595 0.011833333 0.0042 0.00345 0.005326667 0.002176667 0 0 0.003733333 0.006066667 0.013743333
PI 0 0 0 0 0 0 0 0 0 0 0 0 0.006003333 0
;
title3 'Maximum Likelihood Factor Analysis with One Factor';
proc factor data=SsamPAHan method=ml heywood n=1;
title3 'Maximum Likelihood Factor Analysis with Two Factor';
proc factor data=SsamPAHan method=ml heywood n=2;
title3 'Maximum Likelihood Factor Analysis with Three Factor';
proc factor data=SsamPAHan method=ml heywood n=3;

 

 

1 ACCEPTED SOLUTION

Accepted Solutions
PaigeMiller
Diamond | Level 26
NOTE: The data set WORK.SSAMPAHAN has 5 observations and 15 variables.
WARNING: The number of observations is not greater than the number of variables.
ERROR: Correlation matrix is singular.
NOTE: Prior communality estimates will be 1.0.
ERROR: METHOD=ML requires a nonsingular correlation matrix.

If you have 5 records and 15 variables, then mathematically, you are guaranteed to have a singular correlation matrix. So you can't do this analysis unless you have at least (I think) 15 records.

--
Paige Miller

View solution in original post

5 REPLIES 5
PaigeMiller
Diamond | Level 26

Can you show us the full complete log for this portion of code, with nothing chopped out? Please copy the log as text and paste it into the windows that appears when you click on the </> icon here. DO NOT SKIP THIS STEP.

 

Also, showing us the output would help.

--
Paige Miller
Reeza
Super User
Your data structure seems weird, can you please explain your data as well.
rjinks
Obsidian | Level 7

1          OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK;

 72        

 73         Data SsamPAHan;

 74         Input Site $ Ace Anthra Benzoaa Benzoapy

 75         Benzobflu Benzoghi Benzokfluo Chry

 76         Dibenzo Fluoran Fluorene Indeno123

 77         Phenan Pyr;

 78         Datalines;

 

 NOTE: The data set WORK.SSAMPAHAN has 5 observations and 15 variables.

 NOTE: DATA statement used (Total process time):

       real time           0.00 seconds

       cpu time            0.00 seconds

      

 

 84         ;

 85         title3 'Maximum Likelihood Factor Analysis with One Factor';

 86         proc factor data=SsamPAHan method=ml heywood n=1;

 87         title3 'Maximum Likelihood Factor Analysis with Two Factor';

 

 WARNING: The number of observations is not greater than the number of variables.

 ERROR: Correlation matrix is singular.

 NOTE: Prior communality estimates will be 1.0.

 ERROR: METHOD=ML requires a nonsingular correlation matrix.

 NOTE: The SAS System stopped processing this step because of errors.

 NOTE: PROCEDURE FACTOR used (Total process time):

       real time           0.05 seconds

       cpu time            0.05 seconds

      

 

 

 88         proc factor data=SsamPAHan method=ml heywood n=2;

 89         title3 'Maximum Likelihood Factor Analysis with Three Factor';

 

 WARNING: The number of observations is not greater than the number of variables.

 ERROR: Correlation matrix is singular.

 NOTE: Prior communality estimates will be 1.0.

 ERROR: METHOD=ML requires a nonsingular correlation matrix.

 NOTE: The SAS System stopped processing this step because of errors.

 NOTE: PROCEDURE FACTOR used (Total process time):

       real time           0.03 seconds

       cpu time            0.03 seconds

      

 

 

 90         proc factor data=SsamPAHan method=ml heywood n=3;

 91        

 92        

 93        

 94        

 95        

 96        

 97         OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK;

 WARNING: The number of observations is not greater than the number of variables.

 ERROR: Correlation matrix is singular.

 ERROR: METHOD=ML requires a nonsingular correlation matrix.

 109       

PaigeMiller
Diamond | Level 26
NOTE: The data set WORK.SSAMPAHAN has 5 observations and 15 variables.
WARNING: The number of observations is not greater than the number of variables.
ERROR: Correlation matrix is singular.
NOTE: Prior communality estimates will be 1.0.
ERROR: METHOD=ML requires a nonsingular correlation matrix.

If you have 5 records and 15 variables, then mathematically, you are guaranteed to have a singular correlation matrix. So you can't do this analysis unless you have at least (I think) 15 records.

--
Paige Miller
rjinks
Obsidian | Level 7

Thank you. I am reading up on matrices to insure that going forward I have the right conditions for the expected output.

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