Excluded variables from regression

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Excluded variables from regression

mmarkus
Does anyone know why SPSS excludes certain variables from a regression? Also, does anyone know how to prevent this from happening?

Thanks,

Miljan
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Re: Excluded variables from regression

Justin Meyer-3
One reason SPSS will exclude variables from a regression is if they are
not numeric. For example, a gender variable that uses M and F to
represent male and female would have to be recoded as 0 and 1 to be used
in a regression.

____________________________________

Justin Meyer

Rowland Reading Foundation

phone: 866-370-7323  fax: 608-204-3846

____________________________________


-----Original Message-----
From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of
mmarkus
Sent: Friday, January 18, 2008 2:40 PM
To: [hidden email]
Subject: Excluded variables from regression

Does anyone know why SPSS excludes certain variables from a regression?
Also,
does anyone know how to prevent this from happening?

Thanks,

Miljan
--
View this message in context:
http://www.nabble.com/Excluded-variables-from-regression-tp14957806p1495
7806.html
Sent from the SPSSX Discussion mailing list archive at Nabble.com.

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Re: Excluded variables from regression

James Whanger
Another possibility is that you have inadvertantly chosen the "stepwise"
method of variable selection.



On Jan 18, 2008 4:45 PM, Justin Meyer <[hidden email]>
wrote:

> One reason SPSS will exclude variables from a regression is if they are
> not numeric. For example, a gender variable that uses M and F to
> represent male and female would have to be recoded as 0 and 1 to be used
> in a regression.
>
> ____________________________________
>
> Justin Meyer
>
> Rowland Reading Foundation
>
> phone: 866-370-7323  fax: 608-204-3846
>
> ____________________________________
>
>
> -----Original Message-----
> From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of
> mmarkus
> Sent: Friday, January 18, 2008 2:40 PM
> To: [hidden email]
> Subject: Excluded variables from regression
>
> Does anyone know why SPSS excludes certain variables from a regression?
> Also,
> does anyone know how to prevent this from happening?
>
> Thanks,
>
> Miljan
> --
> View this message in context:
> http://www.nabble.com/Excluded-variables-from-regression-tp14957806p1495
> 7806.html
> Sent from the SPSSX Discussion mailing list archive at Nabble.com<http://nabble.com/>
> .
>
> =====================
> To manage your subscription to SPSSX-L, send a message to
> [hidden email] (not to SPSSX-L), with no body text except the
> command. To leave the list, send the command
> SIGNOFF SPSSX-L
> For a list of commands to manage subscriptions, send the command
> INFO REFCARD
>
> =====================
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> [hidden email] (not to SPSSX-L), with no body text except the
> command. To leave the list, send the command
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> INFO REFCARD
>

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Re: Excluded variables from regression

Johnny Amora
If ENTER method is used; that is, if all the
predictors variables (X's) are forced to ENTER in the
regression model, exclusion will possibly occur
especially if some of the X's are highly correlated
(multicollineary problem). Basically, if a set of
predictor variables are highly correlated only one is
included in the regression model and the rest are
excluded.  Why not use SEM, instead of regression?

Johnny


--- "James C. Whanger" <[hidden email]>
wrote:

> Another possibility is that you have inadvertantly
> chosen the "stepwise"
> method of variable selection.
>
>
>
> On Jan 18, 2008 4:45 PM, Justin Meyer
> <[hidden email]>
> wrote:
>
> > One reason SPSS will exclude variables from a
> regression is if they are
> > not numeric. For example, a gender variable that
> uses M and F to
> > represent male and female would have to be recoded
> as 0 and 1 to be used
> > in a regression.
> >
> > ____________________________________
> >
> > Justin Meyer
> >
> > Rowland Reading Foundation
> >
> > phone: 866-370-7323  fax: 608-204-3846
> >
> > ____________________________________
> >
> >
> > -----Original Message-----
> > From: SPSSX(r) Discussion
> [mailto:[hidden email]] On Behalf Of
> > mmarkus
> > Sent: Friday, January 18, 2008 2:40 PM
> > To: [hidden email]
> > Subject: Excluded variables from regression
> >
> > Does anyone know why SPSS excludes certain
> variables from a regression?
> > Also,
> > does anyone know how to prevent this from
> happening?
> >
> > Thanks,
> >
> > Miljan
> > --
> > View this message in context:
> >
>
http://www.nabble.com/Excluded-variables-from-regression-tp14957806p1495

> > 7806.html
> > Sent from the SPSSX Discussion mailing list
> archive at Nabble.com<http://nabble.com/>
> > .
> >
> > =====================
> > To manage your subscription to SPSSX-L, send a
> message to
> > [hidden email] (not to SPSSX-L), with
> no body text except the
> > command. To leave the list, send the command
> > SIGNOFF SPSSX-L
> > For a list of commands to manage subscriptions,
> send the command
> > INFO REFCARD
> >
> > =====================
> > To manage your subscription to SPSSX-L, send a
> message to
> > [hidden email] (not to SPSSX-L), with
> no body text except the
> > command. To leave the list, send the command
> > SIGNOFF SPSSX-L
> > For a list of commands to manage subscriptions,
> send the command
> > INFO REFCARD
> >
>
> =====================
> To manage your subscription to SPSSX-L, send a
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> [hidden email] (not to SPSSX-L), with no
> body text except the
> command. To leave the list, send the command
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> the command
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>



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Re: Excluded variables from regression

CarolineUK
In reply to this post by mmarkus
This question was asked last year...

Does anyone know why SPSS excludes certain variables from a regression?
Also, does anyone know how to prevent this from happening?

There were various offers of help/suggestions:
that the variables excluded were not numeric
That stepwise had been used instead of 'enter'
That there was multicollinearity

I've checked my variables and they contain numeric values, I'm using 'enter'
and the tolerance levels are at least .4 or above.

The background: I'm using hierarchical multiple regression to check for
interaction between a qualitative continuous predictor variable and group
membership.  The continuous predictor variable and dummy variables to denote
group (coded 0 for not in group, 1 for in group) go in block one, along with
some covariate continuous predictor variables.  Then each of the six dummy
variables is linked with one of the continuous predictor variables to create
six product terms and these go in block two.

(For clarity, I'm leaving one group out of the first block and this will be
represented by the constant, but putting all six product terms in block two)

Although SPSS 16 is producing a coefficient table with the sort of results
I'm looking for, it's also producing a second table underneath labelled
'excluded variables' and in this table is all of the product terms (a
centred numeric figure with + or - value x a dummy code of 1).
I'm thinking I can't ignore this table and that it has excluded the
variables for a reason to do with coding?
--
View this message in context: http://old.nabble.com/Excluded-variables-from-regression-tp14957806p27061302.html
Sent from the SPSSX Discussion mailing list archive at Nabble.com.

=====================
To manage your subscription to SPSSX-L, send a message to
[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command
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Re: Excluded variables from regression

ajayohri
In reply to this post by mmarkus
Possible reason for exclusion could be speed of processing

Spss on desktop is slower than say sas for regression BUT things could
be different on grid computers

Does anyone know spss licensing on deploying it on amazon or any other
cloud computer with multiple processors

Regards

Ajay

http:\\decisionstats.com

Sent from my iPhone

On Jan 7, 2010, at 6:59 AM, CarolineUK <[hidden email]> wrote:

> This question was asked last year...
>
> Does anyone know why SPSS excludes certain variables from a
> regression?
> Also, does anyone know how to prevent this from happening?
>
> There were various offers of help/suggestions:
> that the variables excluded were not numeric
> That stepwise had been used instead of 'enter'
> That there was multicollinearity
>
> I've checked my variables and they contain numeric values, I'm using
> 'enter'
> and the tolerance levels are at least .4 or above.
>
> The background: I'm using hierarchical multiple regression to check
> for
> interaction between a qualitative continuous predictor variable and
> group
> membership.  The continuous predictor variable and dummy variables
> to denote
> group (coded 0 for not in group, 1 for in group) go in block one,
> along with
> some covariate continuous predictor variables.  Then each of the six
> dummy
> variables is linked with one of the continuous predictor variables
> to create
> six product terms and these go in block two.
>
> (For clarity, I'm leaving one group out of the first block and this
> will be
> represented by the constant, but putting all six product terms in
> block two)
>
> Although SPSS 16 is producing a coefficient table with the sort of
> results
> I'm looking for, it's also producing a second table underneath
> labelled
> 'excluded variables' and in this table is all of the product terms (a
> centred numeric figure with + or - value x a dummy code of 1).
> I'm thinking I can't ignore this table and that it has excluded the
> variables for a reason to do with coding?
> --
> View this message in context: http://old.nabble.com/Excluded-variables-from-regression-tp14957806p27061302.html
> Sent from the SPSSX Discussion mailing list archive at Nabble.com.
>
> =====================
> To manage your subscription to SPSSX-L, send a message to
> [hidden email] (not to SPSSX-L), with no body text except
> the
> command. To leave the list, send the command
> SIGNOFF SPSSX-L
> For a list of commands to manage subscriptions, send the command
> INFO REFCARD

=====================
To manage your subscription to SPSSX-L, send a message to
[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command
SIGNOFF SPSSX-L
For a list of commands to manage subscriptions, send the command
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Re: Excluded variables from regression

Jon K Peck

Please.  Speed of processing has nothing to do with variable exclusion.  Most likely the product terms are highly collinear or constant.

HTH,
Jon Peck
SPSS, an IBM Company
[hidden email]
312-651-3435



From: AJ <[hidden email]>
To: [hidden email]
Date: 01/07/2010 09:29 AM
Subject: Re: [SPSSX-L] Excluded variables from regression
Sent by: "SPSSX(r) Discussion" <[hidden email]>





Possible reason for exclusion could be speed of processing

Spss on desktop is slower than say sas for regression BUT things could
be different on grid computers

Does anyone know spss licensing on deploying it on amazon or any other
cloud computer with multiple processors

Regards

Ajay

http:\\decisionstats.com

Sent from my iPhone

On Jan 7, 2010, at 6:59 AM, CarolineUK <[hidden email]> wrote:

> This question was asked last year...
>
> Does anyone know why SPSS excludes certain variables from a
> regression?
> Also, does anyone know how to prevent this from happening?
>
> There were various offers of help/suggestions:
> that the variables excluded were not numeric
> That stepwise had been used instead of 'enter'
> That there was multicollinearity
>
> I've checked my variables and they contain numeric values, I'm using
> 'enter'
> and the tolerance levels are at least .4 or above.
>
> The background: I'm using hierarchical multiple regression to check
> for
> interaction between a qualitative continuous predictor variable and
> group
> membership.  The continuous predictor variable and dummy variables
> to denote
> group (coded 0 for not in group, 1 for in group) go in block one,
> along with
> some covariate continuous predictor variables.  Then each of the six
> dummy
> variables is linked with one of the continuous predictor variables
> to create
> six product terms and these go in block two.
>
> (For clarity, I'm leaving one group out of the first block and this
> will be
> represented by the constant, but putting all six product terms in
> block two)
>
> Although SPSS 16 is producing a coefficient table with the sort of
> results
> I'm looking for, it's also producing a second table underneath
> labelled
> 'excluded variables' and in this table is all of the product terms (a
> centred numeric figure with + or - value x a dummy code of 1).
> I'm thinking I can't ignore this table and that it has excluded the
> variables for a reason to do with coding?
> --
> View this message in context:
http://old.nabble.com/Excluded-variables-from-regression-tp14957806p27061302.html
> Sent from the SPSSX Discussion mailing list archive at Nabble.com.
>
> =====================
> To manage your subscription to SPSSX-L, send a message to
> [hidden email] (not to SPSSX-L), with no body text except
> the
> command. To leave the list, send the command
> SIGNOFF SPSSX-L
> For a list of commands to manage subscriptions, send the command
> INFO REFCARD

=====================
To manage your subscription to SPSSX-L, send a message to
[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command
SIGNOFF SPSSX-L
For a list of commands to manage subscriptions, send the command
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Re: Excluded variables from regression

ajayohri
What about Part 2


SPSS on cloud computing?

Ajay

Websites-
http://decisionstats.com
http://dudeofdata.com


Linkedin- www.linkedin.com/in/ajayohri




On Thu, Jan 7, 2010 at 8:38 AM, Jon K Peck <[hidden email]> wrote:

Please.  Speed of processing has nothing to do with variable exclusion.  Most likely the product terms are highly collinear or constant.

HTH,
Jon Peck
SPSS, an IBM Company
[hidden email]
312-651-3435



From: AJ <[hidden email]>
To:
Date: 01/07/2010 09:29 AM
Subject: Re: [SPSSX-L] Excluded variables from regression
Sent by: "SPSSX(r) Discussion" <[hidden email]>





Possible reason for exclusion could be speed of processing

Spss on desktop is slower than say sas for regression BUT things could
be different on grid computers

Does anyone know spss licensing on deploying it on amazon or any other
cloud computer with multiple processors

Regards

Ajay

http:\\decisionstats.com

Sent from my iPhone

On Jan 7, 2010, at 6:59 AM, CarolineUK <[hidden email]> wrote:

> This question was asked last year...
>
> Does anyone know why SPSS excludes certain variables from a
> regression?
> Also, does anyone know how to prevent this from happening?
>
> There were various offers of help/suggestions:
> that the variables excluded were not numeric
> That stepwise had been used instead of 'enter'
> That there was multicollinearity
>
> I've checked my variables and they contain numeric values, I'm using
> 'enter'
> and the tolerance levels are at least .4 or above.
>
> The background: I'm using hierarchical multiple regression to check
> for
> interaction between a qualitative continuous predictor variable and
> group
> membership.  The continuous predictor variable and dummy variables
> to denote
> group (coded 0 for not in group, 1 for in group) go in block one,
> along with
> some covariate continuous predictor variables.  Then each of the six
> dummy
> variables is linked with one of the continuous predictor variables
> to create
> six product terms and these go in block two.
>
> (For clarity, I'm leaving one group out of the first block and this
> will be
> represented by the constant, but putting all six product terms in
> block two)
>
> Although SPSS 16 is producing a coefficient table with the sort of
> results
> I'm looking for, it's also producing a second table underneath
> labelled
> 'excluded variables' and in this table is all of the product terms (a
> centred numeric figure with + or - value x a dummy code of 1).
> I'm thinking I can't ignore this table and that it has excluded the
> variables for a reason to do with coding?
> --
> View this message in context:
http://old.nabble.com/Excluded-variables-from-regression-tp14957806p27061302.html
> Sent from the SPSSX Discussion mailing list archive at Nabble.com.
>
> =====================
> To manage your subscription to SPSSX-L, send a message to
> [hidden email] (not to SPSSX-L), with no body text except
> the
> command. To leave the list, send the command
> SIGNOFF SPSSX-L
> For a list of commands to manage subscriptions, send the command
> INFO REFCARD

=====================
To manage your subscription to SPSSX-L, send a message to
[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command
SIGNOFF SPSSX-L
For a list of commands to manage subscriptions, send the command
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Re: Excluded variables from regression

Bruce Weaver
Administrator
In reply to this post by CarolineUK
CarolineUK wrote
This question was asked last year...

Does anyone know why SPSS excludes certain variables from a regression?
Also, does anyone know how to prevent this from happening?

There were various offers of help/suggestions:
that the variables excluded were not numeric
That stepwise had been used instead of 'enter'
That there was multicollinearity

I've checked my variables and they contain numeric values, I'm using 'enter'
and the tolerance levels are at least .4 or above.

The background: I'm using hierarchical multiple regression to check for
interaction between a qualitative continuous predictor variable and group
membership.  The continuous predictor variable and dummy variables to denote
group (coded 0 for not in group, 1 for in group) go in block one, along with
some covariate continuous predictor variables.  Then each of the six dummy
variables is linked with one of the continuous predictor variables to create
six product terms and these go in block two.

(For clarity, I'm leaving one group out of the first block and this will be
represented by the constant, but putting all six product terms in block two)
--- snip ---

If I follow, there are 6 groups that are coded with 5 indicator variables in block 1.  If that is correct, then the interaction of that GROUP variable with the continuous variable needs to be represented by 5 product terms, not 6.  The 5 product terms are the same 5 indicator variables you have in block 1 multiplied by the continuous variable.  

--
Bruce Weaver
bweaver@lakeheadu.ca
http://sites.google.com/a/lakeheadu.ca/bweaver/

"When all else fails, RTFM."

NOTE: My Hotmail account is not monitored regularly.
To send me an e-mail, please use the address shown above.
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Re: Excluded variables from regression

CarolineUK
You've summed up perfectly Bruce - so as well as leaving out the 'reference group' for the group analysis, I need to leave out the product term which is part made up of that same group?  If so, how do I know how to calculate whether the product term I've left out is significant?  (because you only get one 'constant' line, and that's for the group dummy variable, not the product term derivative of it?)  
Cheers in confusion...


Bruce Weaver wrote
CarolineUK wrote
This question was asked last year...

Does anyone know why SPSS excludes certain variables from a regression?
Also, does anyone know how to prevent this from happening?

There were various offers of help/suggestions:
that the variables excluded were not numeric
That stepwise had been used instead of 'enter'
That there was multicollinearity

I've checked my variables and they contain numeric values, I'm using 'enter'
and the tolerance levels are at least .4 or above.

The background: I'm using hierarchical multiple regression to check for
interaction between a qualitative continuous predictor variable and group
membership.  The continuous predictor variable and dummy variables to denote
group (coded 0 for not in group, 1 for in group) go in block one, along with
some covariate continuous predictor variables.  Then each of the six dummy
variables is linked with one of the continuous predictor variables to create
six product terms and these go in block two.

(For clarity, I'm leaving one group out of the first block and this will be
represented by the constant, but putting all six product terms in block two)
--- snip ---

If I follow, there are 6 groups that are coded with 5 indicator variables in block 1.  If that is correct, then the interaction of that GROUP variable with the continuous variable needs to be represented by 5 product terms, not 6.  The 5 product terms are the same 5 indicator variables you have in block 1 multiplied by the continuous variable.