Test: If the person had known the truth, he/ she would not have entered the agreement or would have entered into the engagement on different terms
Error in persona: Identity of person wrong
Error in negotio: Misrepresentation
Misrepresentation: Both error in persona and error in negotio amounts to misrepresentation
Material mistake- contract is voidable
Mental illness, addiction, impotence can affect consensus
Duress or undue influence can affect consensus