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From |
Erik Aadland <erikaadland@hotmail.com> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
RE: st: RE: creating variable summarizing for each individual properties of other members of a group at t-1 |

Date |
Tue, 17 May 2011 18:38:21 +0000 |

My apologies if I am being imprecise. I am struggling in my attempt to create the following two variables. One variable that yields a score for each individual in the dataset for each yearmonth: the score is the sum of all ind_entry = 1 for all the other individuals excluding the focal individual up until and including time: yearmonth - 1. And a second variable that identifies for each individual in the dataset for each yearmonth: the total number of other individuals in the dataset that have experienced ind_entry = 1 at least once up until and including time: yearmonth - 1. In this variable, I want to count the number of individuals that have experienced ind_entry = 1, not how many times they have entered. Sincerely, Erik Aadland. ---------------------------------------- > From: n.j.cox@durham.ac.uk > To: statalist@hsphsun2.harvard.edu > Date: Tue, 17 May 2011 19:22:50 +0100 > Subject: RE: st: RE: creating variable summarizing for each individual properties of other members of a group at t-1 > > I naturally have no idea what -ind_entry- means. > > I am just summing it, as the code implies. Is that not what you want? > > Nick > n.j.cox@durham.ac.uk > > > -----Original Message----- > From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Erik Aadland > Sent: 17 May 2011 19:14 > To: statalist@hsphsun2.harvard.edu > Subject: RE: st: RE: creating variable summarizing for each individual properties of other members of a group at t-1 > > Thank you so much for your input, Nick. > > I have experimented and generated different variables previously relying on the very helpful FAQ in question. > > I am struggling with this problem however. When I apply the suggested code below, it appears that the calculation of the number of peers adds up more than it should for ind_ids with more ind_entry = 1 relative to other ind_ids, and consequently contribute more to the "score" than those with fewer ind_entry = 1. > > Referring to the example dataset, ind_id 2 is given the correct "prevscore". Ind_id 4, however, is not. By yearmonth 12, ind_id 4 has contributed 2 ind_entry=1 to the "score", which is correct for ind_id 2. However, ind_id 2 has not yet experienced ind_entry=1. Consequently, score - 1 for ind_id 4 yields a score = 1 in yearmonth 11 and 12, when the correct score = 0. And so on. > > Here is the suggested code as I applied it: > > clear ; > #delimit ; > use "ind_entry_ex.dta" ; > sort yearmonth ; > gen score = sum(ind_entry) ; > by yearmonth: replace score = score[_N] ; > replace score = score - ind_entry ; > bysort ind_id (yearmonth): gen prevscore = score[_n-1] ; > > > Here is the output: > > year month yearmonth ind_id ind_entry score prevscore > 2003 10 10 2 0 1 > 2003 11 11 2 0 1 1 > 2003 12 12 2 0 2 1 > 2004 1 13 2 0 2 2 > 2004 2 14 2 1 2 2 > 2004 3 15 2 0 3 2 > 2003 10 10 4 1 0 > 2003 11 11 4 0 1 0 > 2003 12 12 4 1 1 1 > 2004 1 13 4 0 2 1 > 2004 2 14 4 0 3 2 > 2004 3 15 4 0 3 3 > > I use Stata 10. > > > Thanks again and kind regards, > > Erik. > > > ---------------------------------------- > > From: n.j.cox@durham.ac.uk > > To: statalist@hsphsun2.harvard.edu > > Date: Tue, 17 May 2011 17:47:53 +0100 > > Subject: st: RE: creating variable summarizing for each individual properties of other members of a group at t-1 > > > > I don't know what "I am familiar with" means here. Does it mean that you've read the FAQ but can't see how to apply it? > > > > This sounds to me like > > > > 1. Get the sum of all individual entries > > > > sort yearmonth > > gen score = sum(ind_entry) > > by yearmonth : replace score = score[_N] > > > > 2. Subtract this individual > > > > replace score = score - ind_entry > > > > 3. Look one step back in time > > > > bysort ind_id (yearmonth) : gen prevscore = score[_n-1] > > > > Nick > > n.j.cox@durham.ac.uk > > > > Erik Aadland > > > > I need to create a variable that sums for each individual in my dataset the total number of ind_entry of all other individuals at time: yearmonth - 1. > > I have attached a small ex of my data structure below. So for instance, given the small dataset below, for ind_id 2 in yearmonth 11 this variable score = 1. But for ind_id 4 in the same yearmonth, the score = 0. > > > > I would also like to generate a variable that identifies for each individual the unique number of other individuals in the dataset that have experienced ind_entry = 1 at least once up until time: yearmonth - 1. > > > > I am familiar with the following FAQ: http://www.stata.com/support/faqs/data/members.html > > > > My data structure is snapshot data in principle like the example below, but some individuals enter the observation window later than others (i.e. in later yearmonths): > > > > year month yearmonth ind_id ind_entry > > 2003 10 10 2 0 > > 2003 11 11 2 0 > > 2003 12 12 2 0 > > 2004 1 13 2 0 > > 2004 2 14 2 1 > > 2004 3 15 2 0 > > 2003 10 10 4 1 > > 2003 11 11 4 0 > > 2003 12 12 4 1 > > 2004 1 13 4 0 > > 2004 2 14 4 0 > > 2004 3 15 4 0 > > > > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: RE: creating variable summarizing for each individual properties of other members of a group at t-1***From:*Nick Cox <njcoxstata@gmail.com>

**References**:**st: creating variable summarizing for each individual properties of other members of a group at t-1***From:*Erik Aadland <erikaadland@hotmail.com>

**st: RE: creating variable summarizing for each individual properties of other members of a group at t-1***From:*Nick Cox <n.j.cox@durham.ac.uk>

**RE: st: RE: creating variable summarizing for each individual properties of other members of a group at t-1***From:*Erik Aadland <erikaadland@hotmail.com>

**RE: st: RE: creating variable summarizing for each individual properties of other members of a group at t-1***From:*Nick Cox <n.j.cox@durham.ac.uk>

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