How can you say if an advertisement has been effective enough or not?

How can you say if an advertisement has been effective enough or not?

It is important to know whether an advertisement has been effective at all or not.We can evaluate the effectiveness of an advertisement through the following ways:

a.recognition method: showing the people an advertisement and asking them if they have seen it before.

b.aided recall: asking people to recall any brand that they may have or might want to use.

c.unaided recall: asking people if they can remember seeing any ads within an identified product category.