assessment vs calculation

assessment

noun
  • The act of assessing or an amount (of tax, levy or duty etc) assessed. 

  • An appraisal or evaluation. 

calculation

noun
  • The act or process of calculating. 

  • Reckoning, estimate. 

  • The result of calculating. 

  • An expectation based on circumstances. 

  • The act or process of imagining sequences of potential moves and responses without actually moving the pieces. 

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