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From |
Steven Samuels <sjsamuels@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: ratio of 2 different surveys estimates? svyset , suest , fpc , nlcom |

Date |
Fri, 21 Jan 2011 17:32:37 -0500 |

Steve Steven J. Samuels sjsamuels@gmail.com 18 Cantine's Island Saugerties NY 12477 USA Voice: 845-246-0774 Fax: 206-202-4783 On Jan 21, 2011, at 12:57 AM, Roman Kasal wrote: 1) in my case the FPCs in my multistage survey are not much different so not a big problem (but through the time the FPCs can differ - year 2000 and year 2010), but 2) what if I have 2 different multistage surveys that I got (eg found a survey from Germany on internet and the same survey but with completely different FPCs). Is really correct to combine FPCs (eg one stratum with FPC1=0.05 and FPC in the second survey FPC2=0.7)? Could you recommend me any literature? thank you! -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Steven Samuels Sent: Thursday, January 20, 2011 8:16 PM To: statalist@hsphsun2.harvard.edu Subject: Re: st: ratio of 2 different surveys estimates? svyset , suest , fpc , nlcom Austin-- I agree that the interpretation of statistics in the total population is not easy. I recall that you once suggested that the unit for repeated surveys of the same population should be something like a person-year. However Roman seems to be interested in estimating year- to-year differences (or ratios), so, for his purposes, the definition of the total population might not be an issue. The -svyset- statement that I wrote assumes that, aside from certainty PSUs, a new sample of PSUs was drawn in each year. If this is not correct, then a different -svyset- statement is needed. Roman, I'd like to know why fpc's varied greatly and how they were computed. If the survey had several stages and you are interested in primarily descriptive statistics, then perhaps the -svyset- should reflect the multi-stage structure. Steve On Jan 20, 2011, at 12:43 PM, Austin Nichols wrote: Steve-- This works for inference on a population that is the sum of the populations in each of two years--a strange population for many purposes. On Thu, Jan 20, 2011 at 9:00 AM, Steven Samuels <sjsamuels@gmail.com> wrote:

"Is this statistically correct..?" Yes Steve sjsamuels@gmail.com On Jan 20, 2011, at 4:03 AM, Roman Kasal wrote: ok, I understand that, I already did this once, but is this statistically correct adjusting=combine FPCs of two different surveys? What if the FPCs are really very different (this is not mentioned case)? -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Steven Samuels Sent: Wednesday, January 19, 2011 9:08 PM To: statalist@hsphsun2.harvard.edu Subject: Re: st: ratio of 2 different surveys estimates? svyset , suest , fpc , nlcom Another way of putting this: When you combine independent surveys, you must create a new stratum variable in which the individual original strata in each survey appear. You would do this in your data, for example by: **************************** egen stratum =group(year stk) ***************************** If there were 10 strata in 2006 and 10 in 2007, the new stratum variable should have 20 levels. Then a single -svyset- statement will allow joint analysis of the two surveys, as in my example. Steve sjsamuels@gmail.com

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**References**:**st: ratio of 2 different surveys estimates? svyset , suest , fpc , nlcom***From:*"Roman Kasal" <kasal@trexima.cz>

**Re: st: ratio of 2 different surveys estimates? svyset , suest , fpc , nlcom***From:*Steven Samuels <sjsamuels@gmail.com>

**Re: st: ratio of 2 different surveys estimates? svyset , suest , fpc , nlcom***From:*Steven Samuels <sjsamuels@gmail.com>

**RE: st: ratio of 2 different surveys estimates? svyset , suest , fpc , nlcom***From:*"Roman Kasal" <kasal@trexima.cz>

**Re: st: ratio of 2 different surveys estimates? svyset , suest , fpc , nlcom***From:*Steven Samuels <sjsamuels@gmail.com>

**Re: st: ratio of 2 different surveys estimates? svyset , suest , fpc , nlcom***From:*Austin Nichols <austinnichols@gmail.com>

**Re: st: ratio of 2 different surveys estimates? svyset , suest , fpc , nlcom***From:*Steven Samuels <sjsamuels@gmail.com>

**RE: st: ratio of 2 different surveys estimates? svyset , suest , fpc , nlcom***From:*"Roman Kasal" <kasal@trexima.cz>

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