st: Difficult merging process

[Nathan Hutto <nathandavidhutto@gmail.com>]

Hi all,

I am attempting to merge two data sets in a way that is new to am and
am having trouble figuring out how to do so. One data set contains
geo-coded birth certificates and the other contains weather events. I
want to determine whether a mother was exposed to a weather event
during the course of her pregnancy. I have the birth date and
gestational length, so I can determine the dates of gestation by
subtracting one from the other. I also have the latitude and
longitude, address, city, and state of each pregnancy and weather
event. For this case, exposure to a weather event would be defined as
being pregnant when a weather event occurred in close proximity.

I'm ok with over-merging a little bit; I can determine the exact
exposure by using one of Stata's length commands that can calculate
distance with latitude and longitude. But given that many people in my
data are exposed to a number of weather events, I'd like to whittle
down the amount of false positives.

Any thoughts on this?

Thank you,
Nathan
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