in other words vs therefore

in other words

adv
  • used to introduce an explanation, simplification, or clarification 

prep
  • Stated or interpreted another way; Used to introduce an explanation, simplification, or clarification. 

therefore

adv
  • Consequently, by or in consequence of that or this cause; referring to something previously stated. 

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