SRM change with efficiency?

[sdochughes]

Has anyone had there SRM decrease with a decrease in efficiency?
I brewed a 10 gal batch of my Stout the other day and tried a different lautering technique. I got a really poor efficiency and the color of my stout was brown.

 

[hophop]

Less efficiency means less sugar and extraction. So, a "thinner" porter may look like a brown ale.

 

[Freedomfan]

Just to add...

Compensating for a lower gravity due to poor efficiency by adjusting your boil time (boil longer) will result in hitting your desired SRM.

As a rule I always recommend taking a pre-boil gravity reading and adjusting boil time based on this number.