Teffects psmatch

[Saadiq Moledina]

Hi,

I just wanted some advice regarding the teffects psmatch. In the example from Stata on birthweight - the number of observations after the PS matching is the same as the original number before the PS matching. Could I get some guidance/advice as to why that is?

Thanks,

Saadiq

[George Ford]

the weight will be very small or zero, essentially excluding the observation from influence on coefficients, but it remains in the "sample."