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From |
Stephen Cranney <scranney@sas.upenn.edu> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
st: Double loop nested within another double loop |

Date |
Wed, 29 Aug 2012 17:11:24 -0400 |

Hi Statalisters, Forgive me if my description is long. It's a complicated setup. I'm making a population microsimulation program where each observation is an id/year/month combination, with the data ordered by year and month. I recently constructed an initial loop to simulate the first person's reproductive history. After the first person's reproductive history is created, I use the expand command to create "offspring" observations; these observations are then given characteristics based on the parents'. My problem is that I have been unable to insert the code I used to simulate postpartum infertility in the offspring, even though I have been able to make it work for the parent. This is the syntax for the first parent that does do what I want it to (after a back-and-forth on Statalist), which is make a certain number of subsequent months after a birth (simulated by an earlier rbinom command) or miscarriage infertile (monthsofpostpartum= months of postpartum infertility, etc.): local N = _N local monthsofpostpartum = 12 local monthsofpostmiscarriage= 7 forvalues i = 1/`N' { forvalues j= 1/`monthsofpostpartum' { local k = `i' + `j' local s= (`monthsofpostmiscarriage'-`j') + `i' + 1 if conception[`i']==1 & miscarriage[`i']==0 replace conception= .p in `k' if conception[`i']==1 & miscarriage[`i']==1 & `s'>1 replace conception= .m in `s' } } *Then I create offspring: local N = _N forvalues i = 1/`N' { if conception[`i'] == 1 { expand 2, gen(newvar`i') **Here is long code that deletes replicated observations arising from the expand 2 command. It also assigns characteristics such as age as based on parents' age, etc. *This is the code that simulates the conception of a child replace conception= rbinomial(1, probabilityconceive) if conception== .f & newvar`i'==1 *Finally, I want to simply make a loop-within-a-loop (within another double loop), and stick the syntax below right below the syntax *above in order to replicate infertile post-partum and post-miscarriage months. However, when I stick it in it doesn't work (although *it doesn't stop the code either--it just doesn't change anything), even though it worked for the first generation before the loops got *started. local N = _N local monthsofpostpartum = 12 local monthsofpostmiscarriage= 7 forvalues z = 1/`N' { forvalues j= 1/`monthsofpostpartum' { local k = `z' + `j' local s= (`monthsofpostmiscarriage'-`j') + `z' + 1 if conception[`i']==1 & miscarriage[`i']==0 & newvar`i'==1 replace conception= .p in `k' if conception[`i']==1 & miscarriage[`i']==1 & `s'>1 & newvar`i'==1 replace conception= .m in `s' } } *And then the code continues on for a while until it ends. Apologies again for the length of this problem. Thanks in advance. Stephen * * 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/

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