# questions on LOGISTIC REGRESSION, to determine a comparison group

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## questions on LOGISTIC REGRESSION, to determine a comparison group

 We are studying academic performance for those who went to a 1-year prep school vs. a comparison group of similar students who did not go to the prep school, then compare them in their freshmen and sophomore years. I am picking up a study from last year and the author is unavailable (and I was the best choice to learn SPSS). I've gotten through "SPSS 101" and need a little help understanding this LOGISTIC REGRESSION. I did look at the General Syntax reference but that kind of made my eyes glaze over ... I see the general approach as to what is happening but need to understand more in depth how it works. My main question is "What's happening [below] to put students into PGROUP group_2020?" *Setup logic (lumps Direct Entry and Prep School all together) IF (feeder1=DIRECT-ENTRY AND classyear < 2021 AND classyear > 2016) prop_filter_2020_4years = 1. IF (feeder1=PREP-SCHOOL AND classyear < 2021 AND classyear > 2016) prop_filter_2020_4years = 1. VALUE LABELS prop_filter_2020_4years 1 'Direct Entry 2017-2020 and Prep School 2017-2020'. *creates PROB GROUPS for 2020. *Here it filters on the above variable prop_filter_2020_4years,  then does Regression calculation *THIS IS MY MAIN QUESTION - What's happening here to put students into PGROUP group_2020? * prop_2020 has a label in the Data View "Predicted Probability", with no values * group_2020 has a label "Predicted Group", with the (translated) values DIRECT-ENTRY, PREP-SCHOOL, etc. FILTER by prop_filter_2020_4years. LOGISTIC REGRESSION VARIABLES feeder1   /METHOD=ENTER Ethnicity1 satmath satverbal gender1 hs_percent   /SAVE=PRED (prop_2020) PGROUP (group_2020). FILTER off. *Later logic, giving me the Direct Entry Comparison Group for GPA's DO IF (feeder1 = DIRECT-ENTRY AND group_2020 = PREP-SCHOOL AND classyear < 2021 AND classyear > 2016). COMPUTE qpa_comp_only_2020 =1. *So here's my Comparison Group based on the above VALUE LABELS qpa_comp_only_2020 1 'Direct Entry Comparison Group 2017-2020' Thanks! ===================== 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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## Re: questions on LOGISTIC REGRESSION, to determine a comparison group

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## Re: questions on LOGISTIC REGRESSION, to determine a comparison group

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## Re: questions on LOGISTIC REGRESSION, to determine a comparison group

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## Re: questions on LOGISTIC REGRESSION, to determine a comparison group

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## Re: questions on LOGISTIC REGRESSION, to determine a comparison group

 True.  I passed that along to the keepers of the CSR.On Mon, Feb 4, 2019 at 11:31 AM Bruce Weaver <[hidden email]> wrote:Thanks Jon, that helps.  It would be nice to have a pointer to CASEWISE in the documentation for SAVE.  https://www.ibm.com/support/knowledgecenter/en/SSLVMB_25.0.0/statistics_reference_project_ddita/spss/regression/syn_logistic_regression_casewise.html Jon Peck wrote > PGROUP and all the other variables that can be saved are listed under the > CASESWISE subcommand. > > On Mon, Feb 4, 2019 at 9:36 AM Bruce Weaver < > bruce.weaver@ > > > wrote: > >> Hi William.  Unfortunately, the CSR manual is not very helpful here, as >> it >> does not mention PGROUP specifically. >> >> >> https://www.ibm.com/support/knowledgecenter/en/SSLVMB_25.0.0/statistics_reference_project_ddita/spss/regression/syn_logistic_regression_save.html > > --- snip --- ----- -- Bruce Weaver [hidden email] 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. -- Sent from: http://spssx-discussion.1045642.n5.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 -- Jon K Peck[hidden email] ===================== 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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## Re: questions on LOGISTIC REGRESSION, to determine a comparison group

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## Re: questions on LOGISTIC REGRESSION, to determine a comparison group

 In reply to this post by Bill Peck I have concerns about the following. DIRECT-ENTRY AND PREP-SCHOOL are not valid variable names if - is a regular minus sign.   Please double check your results. "*Setup logic (lumps Direct Entry and Prep School all together) IF (feeder1=DIRECT-ENTRY AND classyear < 2021 AND classyear > 2016) prop_filter_2020_4years = 1. IF (feeder1=PREP-SCHOOL AND classyear < 2021 AND classyear > 2016) prop_filter_2020_4years = 1. VALUE LABELS prop_filter_2020_4years 1 'Direct Entry 2017-2020 and Prep School 2017-2020'." ===================== 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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## Re: questions on LOGISTIC REGRESSION, to determine a comparison group

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