Dear Kosuke, Many thanks for your kind answer. So I have to do the exact matching subclassification "by hand" I guess (doing as many matching as subclasses and then merging everything into a larger dataset) May I hope then that this option will be implemented in a future update ? ;-) Best Regards, On 6 September 2011 17:37, Kosuke Imai <kimai(a)princeton.edu> wrote: > If exact matching is not available, then you may have to do matching within a subset of the data which has the same values of certain covariates. > > Kosuke > > Department of Politics > Princeton University > http://imai.princeton.edu > > On Aug 29, 2011, at 9:30 AM, John Litfiba wrote: > >> Dear Matchitlist, >> >> Many thanks for that incredible and useful software that solves >> (almost) all my matching problems ... >> >> I would like to know if it is possible to use something similar to the >> "exact" option in nearest neighbor matching for all the others >> matching algorithms.. >> That is, for example, apply a genetic algorithm but being able to >> obtain matches that have absolutely the same values for, lets say, >> their date of birth or any other string or numeric variable... >> >> >> Many thanks in advance, >> Best >> >> -- >> MatchIt mailing list served by Harvard-MIT Data Center >> List Address: matchit(a)lists.gking.harvard.edu >> Subscribe/Unsubscribe: http://lists.gking.harvard.edu/?info=matchit >> MatchIt Software and Documentation: http://gking.harvard.edu/matchit/ >> Browse/Search List Archive: http://lists.hmdc.harvard.edu/lists/matchit/ > >

Dear Kosuke, Indeed, but only for nearest neighbor matching if I understood correcly the Matchit documentation On 7 September 2011 03:17, Kosuke Imai <kimai(a)princeton.edu> wrote: > You can do exact matching using MatchIt. > > Kosuke > > Department of Politics > Princeton University > http://imai.princeton.edu > > On Sep 6, 2011, at 11:54 AM, John Litfiba wrote: > >> Dear Kosuke, >> >> Many thanks for your kind answer. >> So I have to do the exact matching subclassification "by hand" I guess >> (doing as many matching as subclasses and then merging everything into >> a larger dataset) >> May I hope then that this option will be implemented in a future update ? ;-) >> >> Best Regards, >> >> On 6 September 2011 17:37, Kosuke Imai <kimai(a)princeton.edu> wrote: >>> If exact matching is not available, then you may have to do matching within a subset of the data which has the same values of certain covariates. >>> >>> Kosuke >>> >>> Department of Politics >>> Princeton University >>> http://imai.princeton.edu >>> >>> On Aug 29, 2011, at 9:30 AM, John Litfiba wrote: >>> >>>> Dear Matchitlist, >>>> >>>> Many thanks for that incredible and useful software that solves >>>> (almost) all my matching problems ... >>>> >>>> I would like to know if it is possible to use something similar to the >>>> "exact" option in nearest neighbor matching for all the others >>>> matching algorithms.. >>>> That is, for example, apply a genetic algorithm but being able to >>>> obtain matches that have absolutely the same values for, lets say, >>>> their date of birth or any other string or numeric variable... >>>> >>>> >>>> Many thanks in advance, >>>> Best >>>> >>>> -- >>>> MatchIt mailing list served by Harvard-MIT Data Center >>>> List Address: matchit(a)lists.gking.harvard.edu >>>> Subscribe/Unsubscribe: http://lists.gking.harvard.edu/?info=matchit >>>> MatchIt Software and Documentation: http://gking.harvard.edu/matchit/ >>>> Browse/Search List Archive: http://lists.hmdc.harvard.edu/lists/matchit/ >>> >>> > >

Dead Kosuke, Thank you for you answer but I mean not using a exact matching procedure, but instead, as proposed (only?) in the nearest neighbor algorithm with the option exact=c(VAR1, VAR2, etc), specify a subset of my covariates where matching must be exact. The chosen algorithm (either genetic, coarsed, et) is then applied on the remaining covariates. On 7 September 2011 14:27, Kosuke Imai <kimai(a)princeton.edu> wrote: > Try match = "exact" > > Kosuke > > Department of Politics > Princeton University > http://imai.princeton.edu > > On Sep 7, 2011, at 7:02 AM, John Litfiba wrote: > >> Dear Kosuke, >> >> Indeed, but only for nearest neighbor matching if I understood >> correcly the Matchit documentation >> >> On 7 September 2011 03:17, Kosuke Imai <kimai(a)princeton.edu> wrote: >>> You can do exact matching using MatchIt. >>> >>> Kosuke >>> >>> Department of Politics >>> Princeton University >>> http://imai.princeton.edu >>> >>> On Sep 6, 2011, at 11:54 AM, John Litfiba wrote: >>> >>>> Dear Kosuke, >>>> >>>> Many thanks for your kind answer. >>>> So I have to do the exact matching subclassification "by hand" I guess >>>> (doing as many matching as subclasses and then merging everything into >>>> a larger dataset) >>>> May I hope then that this option will be implemented in a future update ? ;-) >>>> >>>> Best Regards, >>>> >>>> On 6 September 2011 17:37, Kosuke Imai <kimai(a)princeton.edu> wrote: >>>>> If exact matching is not available, then you may have to do matching within a subset of the data which has the same values of certain covariates. >>>>> >>>>> Kosuke >>>>> >>>>> Department of Politics >>>>> Princeton University >>>>> http://imai.princeton.edu >>>>> >>>>> On Aug 29, 2011, at 9:30 AM, John Litfiba wrote: >>>>> >>>>>> Dear Matchitlist, >>>>>> >>>>>> Many thanks for that incredible and useful software that solves >>>>>> (almost) all my matching problems ... >>>>>> >>>>>> I would like to know if it is possible to use something similar to the >>>>>> "exact" option in nearest neighbor matching for all the others >>>>>> matching algorithms.. >>>>>> That is, for example, apply a genetic algorithm but being able to >>>>>> obtain matches that have absolutely the same values for, lets say, >>>>>> their date of birth or any other string or numeric variable... >>>>>> >>>>>> >>>>>> Many thanks in advance, >>>>>> Best >>>>>> >>>>>> -- >>>>>> MatchIt mailing list served by Harvard-MIT Data Center >>>>>> List Address: matchit(a)lists.gking.harvard.edu >>>>>> Subscribe/Unsubscribe: http://lists.gking.harvard.edu/?info=matchit >>>>>> MatchIt Software and Documentation: http://gking.harvard.edu/matchit/ >>>>>> Browse/Search List Archive: http://lists.hmdc.harvard.edu/lists/matchit/ >>>>> >>>>> >>> >>> > >