What is considered as the time since PhD degree granted? In certain postdoc positions, the eligibility criteria says, &quot;candidate's PhD has received their PhD within last 4 years.&quot;
So, if I defended on December 2019 and got my degree (convocation) on May 2020. Started postdoc from June 2020. So will my 4 years from now will be calculated on the basis of May 2020 or December 2019?
Major competitions for postdoctoral fellowships have detailed rules which answer this question, but in different ways.  Some use the date the degree was awarded.  Others use the date of the defense or viva.
If it is not specified, assume the later date is used.