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From |
Austin Nichols <austinnichols@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Predicting number of cases |

Date |
Sun, 5 Dec 2010 08:32:38 -0500 |

Christiana Titaley <christiana.titaley@gmail.com>: No, your understanding is wrong; there is no estimate for time 2, so the only equation -predict- can possibly be using is based on time 1 estimates. It's still not clear to me what you intend doing, but maybe you just want to show density estimates like below. See also -oaxaca-, -jmpierce, -jmpierce2, and -dfl- on SSC, and references therein for additional approaches; also http://www.stata.com/statalist/archive/2009-07/msg00602.html u if t==1 using http://www.stata-press.com/data/r11/psidextract, clear g wage=exp(lwage) qui poisson wage south smsa fem union ed blk predict hat keep t hat lwage wage tempfile t1 save `t1' qui forv i=2/7 { u if t==`i' using http://www.stata-press.com/data/r11/psidextract, clear predict hat`i' keep t hat`i' lwage g w`i'=exp(lwage) append using `t1' tempfile t1 save `t1', replace } tw kdensity hat||kdensity hat2||kdensity hat4||kdensity hat7 tw kdensity w4||kdensity hat4||kdensity w7||kdensity hat7 On Sun, Dec 5, 2010 at 12:31 AM, Christiana Titaley <christiana.titaley@gmail.com> wrote: > Hi Austin, > > Thank you for your response. What I want to do is to examine the > trends of neonatal deaths across 5 surveys; whether the changes in the > predictors included in the Poisson model contributed to the reduction > of neonatal deaths over time. > > E.g, using the grunfeld dataset, > > u if time==1 using http://www.stata-press.com/data/r11/grunfeld.dta, clear > poisson invest mvalue kstock, r > predict hat > > This will give me the predicted number of hat for time 1 and also the > predicted equation. I want to apply this equation (time 1) to the > subsequent data (time 2, 3 ...) to get the predicted number of "hat" > by controlling for the same set of predictors (mvalue, kstock). At the > end, I will compare the observed and predicted numbers of hat. > > Please correct me if I'm wrong, but my understanding from the command > below is it uses the equation from time 2, instead of time 1, to get the > number of hat for year 2: > u if time==2 using http://www.stata-press.com/data/r11/grunfeld.dta, clear > predict hat > li hat mvalue, clean > > Do you have any idea what command I can use to apply the first > equation (time 1) to the subsequent survey data? > > Thank you very much. > > Christiana > > > On Fri, Dec 3, 2010 at 12:00 AM, Austin Nichols <austinnichols@gmail.com> wrote: >> Christiana Titaley <christiana.titaley@gmail.com> : >> Use -predict- e.g. >> >> u if time==1 using http://www.stata-press.com/data/r11/grunfeld.dta, clear >> poisson invest mvalue kstock, r >> predict hat >> li hat mvalue, clean >> u if time==2 using http://www.stata-press.com/data/r11/grunfeld.dta, clear >> predict hat >> li hat mvalue, clean >> >> But can you explain the rationale for what you are doing? >> >> >> On Thu, Dec 2, 2010 at 5:15 AM, Christiana Titaley >> <christiana.titaley@gmail.com> wrote: >>> Hi all, >>> >>> I have data from 5 subsequent health surveys. Using data from the >>> first survey, I constructed a Poisson model using a set of potential >>> predictors to examine factors associated with neonatal death. The >>> final model gave me a predictive equation. Then I’d like to apply this >>> predictive equation to the data from subsequent years to determine the >>> predicted number of neonatal death cases. What command should I use >>> for this? >>> >>> Thank you very much. >>> >>> Christiana >>> University of Sydney * * 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/

**References**:**st: Predicting number of cases***From:*Christiana Titaley <christiana.titaley@gmail.com>

**Re: st: Predicting number of cases***From:*Austin Nichols <austinnichols@gmail.com>

**Re: st: Predicting number of cases***From:*Christiana Titaley <christiana.titaley@gmail.com>

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