
We just want to keep her
a little longer for OBSERVATION.
The Big Bang Theory Season 7, Episode 15

I have a conclusion
based on an OBSERVATION.
The Big Bang Theory Season 1, Episode 10

True. I've had a similar OBSERVATION.
The Big Bang Theory Season 2, Episode 15

...correcting for OBSERVATION bias
and postulate an initial dating age of 15...
The Big Bang Theory Season 4, Episode 1