Communication skills (S/P)

[fleetkid]

Which is correct:

1. Communication skills was the single most important factor (.. in an interview)

2. Communication skills were the single most important factor (.. in an interview)

Please explain

[sunnyjohn]

WAS.

flip it:

In an interview the single most factor was comm. skills.

WRONG:
In an interview the single most factor were comm. skills.


I think "IS" is even better that "was".