# variability + singular or plural verb

The sentence is

Variability in data is considered a nuisance.

Variability in data are considered a nuisance.

Initially I thought is was the correct one, but it was corrected to be are. I want to know the reason.

• You were right. Is is correct. "Variability in data" is taken as a whole to be a singular subject. – Jim Aug 6 '14 at 1:33