# Linear trend test when using logistic regression model

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## Linear trend test when using logistic regression model

 Hello   Using SPSS, is it possible to perform a chi-square test of linear trend within the context of a binary logistic regression model? The idea I have in mind here can best be illustrated by an example. Suppose I wish to determine whether there is a linear association between the factor level of exposure (in categories) and the dependent variable disease status (with categories present or absent) whilst adjusting for the effect of other factors such as family history of disease' and gender.   I suspect that that such a test exists but relevant output is not forthcoming from the output for a binary logistic regression analysis within SPSS (on assuming the 'point and click' approach). Some advice would be very much appreciated!   Many thanks for your interest in this request.   Best wishes   Margaret  Send instant messages to your online friends http://uk.messenger.yahoo.com
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## Re: Linear trend test when using logistic regression model

 Hi Margaret Monday, November 27, 2006, 2:04:05 PM, You wrote: MM>   Using SPSS, is it possible to perform a chi-square test of MM> linear trend within the context of a binary logistic regression MM> model? The idea I have in mind here can best be illustrated by an MM> example. Suppose I wish to determine whether there is a linear MM> association between the factor level of exposure (in categories) MM> and the dependent variable disease status (with categories MM> present or absent) whilst adjusting for the effect of other MM> factors such as family history of disease' and gender. use  /CONTRAST (LevelOfExposure)=Polynomial It will decompose LevelOfExposure in k-1 (k:Nr. of levels) variables. The first one will test the linear trend, the second one the quadratic term, and so on. MM>   I suspect that that such a test exists but relevant output MM> is not forthcoming from the output for a binary logistic MM> regression analysis within SPSS (on assuming the 'point and click' MM> approach). -- Regards, Dr. Marta García-Granero,PhD           mailto:[hidden email] Statistician --- "It is unwise to use a statistical procedure whose use one does not understand. SPSS syntax guide cannot supply this knowledge, and it is certainly no substitute for the basic understanding of statistics and statistical thinking that is essential for the wise choice of methods and the correct interpretation of their results". (Adapted from WinPepi manual - I'm sure Joe Abrahmson will not mind)
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## Re: Linear trend test when using logistic regression model

 Dear Marta   Thank you very much. This is most interesting and helpful.   I take it that this test allows you to adjust for the other factors in the model so as to measure the strength of the independent linear relationship between a given factor and the dependent variable.   Could somebody please guide me to a reference which explains the calculations involved in this particular version of the chi-square test of association.   Many thanks   Best wishes   Margaret Marta García-Granero <[hidden email]> wrote:   Hi Margaret Monday, November 27, 2006, 2:04:05 PM, You wrote: MM> Using SPSS, is it possible to perform a chi-square test of MM> linear trend within the context of a binary logistic regression MM> model? The idea I have in mind here can best be illustrated by an MM> example. Suppose I wish to determine whether there is a linear MM> association between the factor level of exposure (in categories) MM> and the dependent variable disease status (with categories MM> present or absent) whilst adjusting for the effect of other MM> factors such as family history of disease' and gender. use /CONTRAST (LevelOfExposure)=Polynomial It will decompose LevelOfExposure in k-1 (k:Nr. of levels) variables. The first one will test the linear trend, the second one the quadratic term, and so on. MM> I suspect that that such a test exists but relevant output MM> is not forthcoming from the output for a binary logistic MM> regression analysis within SPSS (on assuming the 'point and click' MM> approach). -- Regards, Dr. Marta García-Granero,PhD mailto:[hidden email] Statistician --- "It is unwise to use a statistical procedure whose use one does not understand. SPSS syntax guide cannot supply this knowledge, and it is certainly no substitute for the basic understanding of statistics and statistical thinking that is essential for the wise choice of methods and the correct interpretation of their results". (Adapted from WinPepi manual - I'm sure Joe Abrahmson will not mind)  Send instant messages to your online friends http://uk.messenger.yahoo.com