Hi,
I am using Stata 12.1/SE on a windows PC.
I have a question regarding overlapping markets. Each firm and all its competitors within 2 miles are considered as one market.
The data looks like this.
firm1(i.e. market center) firm2 (i.e.competitor_within_2miles) price_difference
A B 1
A C 3
A D 2
A E 4
B A 1
B C 1
B E 5
B Z 2
C A 3
C B 1
C X 9
C Y 7
Since firm pairs are not independent, I want to consider just non-overlapping markets.
Therefore I need to drop some markets.
Since I consider firms within 2 miles, my idea was drop all other markets within 4 miles, so that there cannot be any overlapping markets, because the rardii don't overlap.
I just don't know how to tell Stata to do that and how to randomize this process, so that dropping markets is not biased.
Any ideas?
Best
Christoph
I am using Stata 12.1/SE on a windows PC.
I have a question regarding overlapping markets. Each firm and all its competitors within 2 miles are considered as one market.
The data looks like this.
firm1(i.e. market center) firm2 (i.e.competitor_within_2miles) price_difference
A B 1
A C 3
A D 2
A E 4
B A 1
B C 1
B E 5
B Z 2
C A 3
C B 1
C X 9
C Y 7
Since firm pairs are not independent, I want to consider just non-overlapping markets.
Therefore I need to drop some markets.
Since I consider firms within 2 miles, my idea was drop all other markets within 4 miles, so that there cannot be any overlapping markets, because the rardii don't overlap.
I just don't know how to tell Stata to do that and how to randomize this process, so that dropping markets is not biased.
Any ideas?
Best
Christoph
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