# AFNI Message Board

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 May 01, 2021 08:44AM Admin Registered: 9 years ago Posts: 2,487
Welcome Agent 007!

> -model "Time*Group+Age+Gender+(1|Subj)" \

With a longitudinal study, you may try to account for varying slope effect:

-model "Time*Group+Age+Gender+(Time|Subj)" \

> The effect of Group at Time 0 (?):
> -gltCode Group1-Group2 'Group : 1*Group1 -1*Group2' \

By default, 3dLMEr centers a quantitative variable around its overall average across all subjects. So, the above specification makes inference about group difference at the average time. For Time 0, try

-gltCode Group1-Group2 'Group : 1*Group1 -1*Group2 Time : 0' \

Your current model assumes a linear relationship of Time. In case nonlinearity is of interest, consider 3dMSS.

Gang
Subject Author Posted

#### Contrasts for longitudinal 3dLMEr

AFNIuser007 April 30, 2021 10:11AM

#### Re: Contrasts for longitudinal 3dLMEr

Gang May 01, 2021 08:44AM

#### Re: Contrasts for longitudinal 3dLMEr

AFNIuser007 May 01, 2021 11:53AM

#### Re: Contrasts for longitudinal 3dLMEr

Gang May 01, 2021 04:37PM

#### Re: Contrasts for longitudinal 3dLMEr

AFNIuser007 May 01, 2021 09:00PM

#### Re: Contrasts for longitudinal 3dLMEr

Gang May 02, 2021 09:00AM

#### Re: Contrasts for longitudinal 3dLMEr

AFNIuser007 May 02, 2021 10:30AM

#### Re: Contrasts for longitudinal 3dLMEr

AFNIuser007 May 13, 2021 12:31PM

#### Re: Contrasts for longitudinal 3dLMEr

Gang May 13, 2021 10:12PM

#### Re: Contrasts for longitudinal 3dLMEr

AFNIuser007 May 16, 2021 07:07AM

#### Re: Contrasts for longitudinal 3dLMEr

Gang May 17, 2021 07:34AM

#### Re: Contrasts for longitudinal 3dLMEr

AFNIuser007 May 25, 2021 03:37PM

#### Re: Contrasts for longitudinal 3dLMEr

Gang May 26, 2021 01:06PM

#### Re: Contrasts for longitudinal 3dLMEr

AFNIuser007 May 27, 2021 04:11PM

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