corroboration vs validation

corroboration

noun
  • The act of corroborating, strengthening, or confirming; addition of strength; confirmation 

  • That which corroborates. 

validation

noun
  • The act of validating something. 

  • Something, such as a certificate, that validates something; attestation, authentication, confirmation, proof or verification. 

  • The process of identifying a new prisoner's gang affiliation. 

  • The process whereby others confirm the validity of one's emotions. 

How often have the words corroboration and validation occurred in a corpus of books? (source: Google Ngram Viewer )