You&#x27;re right, I had a paragraph is on getting the number but this is obviously thin ice, so I dropped it for now. I&#x27;m out of ideas on how to measure it, I probably would ask a group of developers, let them make an educated estimation and then make a best effort estimation based on their answers, perhaps something like the Delphi Method [1]<p>&quot;OTOH, the cost to migrate can never be greater than the cost to rewrite from scratch, since rewriting from scratch is a method of migrating.&quot;<p>Interesting point. I need to work on the definitions as obviously &#x27;migration&#x27; is not clear cut enough.<p>[1] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Delphi_method" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Delphi_method</a>