Does having alumni recommendation really make a difference?

[DBear]

Hi all -

I've heard over the years that having a LOR from a professor or someone who's from the school you're applying to helps and I was wondering if this really does make a difference.

I'm thinking it won't be a determining factor but.. I could be wrong.. 

Anyone have thoughts on this? 

[Edotdl]

I feel like it helps to the extent that the professors will know the letter writer better if they are an alumnus of the school/program. If your letter writers are well known within the field then it should not really matter whether or not they went to the school you're applying to.