For faculty positions that require three years of research experience excluding PhD, how is that time calculated? Usually an applicant for a faculty position in different Indian academic institutes requires to have at least three years of research experience excluding his/her PhD. The time span may differ depending on the institutes and/or particular country. I was wondering how does one calculate the time span of research experience? 

More particularly, does that 'experience' start with just joining a postdoc position or defending  one's thesis or only after obtaining the formal degree?
According to recent notification from UGC, research experience during PhD can also be included for teaching post.

Specially, in a notice dated 1 March 2016, it says:


  The issue regarding counting of the period of active service spent on pursuing Ph.D. was considered by the UGC in its 512th Meeting held on 4th February, 2016.
  
  The clarification of University Grants Commission is as follows:
  
  "the period of active service spent on pursuing Research Degree i.e. for
  acquiring Ph.D. degree simultaneously without taking any kind of leave may be counted as teaching experience for the purpose of direct
  recruitment/promotion to the post of Associate Professor and above."