Hi Bill,
Thank you. I appreciate your detailed explanations. I understand that
your suggestion was apt if I were to do some sot of a pair-wise
analysis, which I don't intend to do immediately; but it's still great
to know.
Thanks again,
Joe.
On Fri, Jun 5, 2009 at 4:04 PM, William Gould, StataCorp
LP<[email protected]> wrote:
> In the thread about using Mata to create a matrix of the number of
> agreements between firms, and in response to my last posting,
> Joe. J. said the first part was "exactly what I was looking for"
> and wondered politely why I had felt obligated to add the
> second part. To remind you, in the final iteration of the first
> part, the resulting data looks like this,
>
> +-------------------------------------------------+
> | company f_11A f_11K f_12Z f_14T f_21S |
> |-------------------------------------------------|
> 1. | 11A 0 0 2 1 0 |
> 2. | 11K 0 0 1 0 1 |
> 3. | 12Z 2 1 0 1 1 |
> 4. | 14T 1 0 1 0 0 |
> 5. | 21S 0 1 1 0 0 |
> +-------------------------------------------------+
>
> and in the part I felt obligated to add, I recorded the data like this:
>
> +-----------------------------------+
> | c1 c2 company1 company2 n |
> |-----------------------------------|
> 1. | 1 2 11A 11K 0 |
> 2. | 1 3 11A 12Z 2 |
> 3. | 1 4 11A 14T 1 |
> 4. | 1 5 11A 21S 0 |
> 5. | 2 3 11K 12Z 1 |
> |-----------------------------------|
> 6. | 2 4 11K 14T 0 |
> 7. | 2 5 11K 21S 1 |
> 8. | 3 4 12Z 14T 1 |
> 9. | 3 5 12Z 21S 1 |
> 10. | 4 5 14T 21S 0 |
> +-----------------------------------+
>
> There were two reasons for my unasked-for suggestion.
>
> First, Joe mentioned something about merging in the characteristics of the
> firms and, looking at the first organization, that looked hard to do.
> Obviously, it would be easy to merge in the characteristics of one of the
> parties -- the one recorded in the variable company -- but what about the
> characteristics of the other parties? In the first observation, for
> instance, also needed would be the characteristics of 12Z and 14T.
>
> That lead me to the second organization, where each observation records a pair
> of the parties and so that parties are on equal footing. One could merge in
> characteristics of company1 and of company2 into the data easily.
>
> Second, I thought to myself, how would I analyze these data? I should hasten
> to add that I am not an expert or at least have to reason to think that I am,
> since I don't even know the details of the problem. Were those details
> revealed, I could prove I'm not an expert. Anyway, I wasn't sure what I would
> do with these data in the first organization, but how to analyze them in
> the second organization seemed obvious to me. I could use logistic or
> Poisson regression, or even a hurdle model. To be explained would be whether
> (or how many) agreements there were between pairs of companies based on their
> characteristics and, presumably, interactions of their characteristics.
>
> -- Bill
> [email protected]
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