An effect is, always, a noun. One may speak of the rainbow effect, special effects or, if one is a fan of the electric guitar, an effects pedal like Ibanez’s Tube Screamer[1] or Jim Dunlop’s Cry-Baby Wah-Wah[2].

The original TS-808 Tube Screamer - everything you need for that fat, creamy, crying tone.

Put those two puppies together: now that’s an effect.

But one must not use effect as a verb, even as a space-filler, however clamorously your inner articled clerk implores you to. “Effect” is the weakest verb in the English language. Whatever you are intending to “effect” is almost certain to be a nominalisation of a stronger, better verb; one better suited to the task you have in mind.

Why say “effect the conversion of shares” when you mean “convert the shares”?
Why say “effect the delivey of a notice” when you mean “deliver a notice”?
Why say “effect the butchery of a perfectly good sentence” when you mean -

Well, you get the point.

See also

Plain English Anatomy™ Noun | Verb | Adjective | Adverb | Preposition | Conjunction | Latin | Germany | Flannel | Legal triplicate | Nominalisation | Murder your darlings

References