st: PSMATCH with 2 conditions

["Mihai-Andrei Popescu-Greaca" <mischai@gmx.de>]

PSMATCH only IF

Dear Statalist users,
I am writing a study on the performance of Private Equity (PE) vs.
Non-Private Equity (NPE) backed IPOs. In order to eliminate the endogenity
of being PE-backed, I want to perform propensity score matching by applying
both local linear regression and k-nearest neighbors methods.

My depvar is PE_backed
My [indepvars] are balance sheet and income statement figures like sales,
total assets, operating income, etc.
My outcome is the buy-and-hold-return 4 years after the IPO

In my dataset I created a variable which takes values from 1 to 15, each
number corresponding to the industry the PE- or NPE-backed firm belongs to.
I also have a variable which indicates the year when the IPO occurred.

Now my question: I want to match firms with each other, ONLY if they belong
to the same industry and if the IPO occurred in the same YEAR. In other
words, match firm A (PE-backed) with the firm B (NPE-backed) for which the
distance between their propensity scores is the smallest AND they belong to
the same industry and their IPOs occurred in the same year.
How can I compute this with psmatch2?

Thanks
Mihai

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