While the general rule is words like "evidence", "knowledge" are considered singular and thus the verb that follows should be in the singular form, somehow the following sentence feels like it can use a verb in the plural form. Is this correct ?
"The diagnosis would be based on clinical, biochemical and, in some cases, in vitro evidence that validate the disease status."
Best Answer
No!
The subject word that defines the verb here is evidence.
And the evidence validates regardless of what kind of evidence it is or from how many sources it comes.
It's a bit like saying:
It's the attraction of various kinds that requires the singular verb.
However, you could use the plural if you changed your sentence to read:
Here the plural validate refers back to both analysis and evidence.