Large declines in rates will likely gain the attention of the media.

Lock-in effect refers to borrowers who may wish to avoid the costs of a new mortgage which likely consists of a higher mortgage rate.

Burnout effect can be described as follows: consider a mortgage pool that was formed when rates were 8%, then interest rates dropped to 5%, rose to 8%, and then dropped again to 5%. Many homeowners will have refinanced when interest rates dipped the first time. On the second occurrence of 5% interest rates, most owners in the pool who were able to refinance would have already done so.

There is no such thing as a refinance effect per se.