since and after "year"

Question

Example: Plot the data in your calculator, where x represents the number of years "since" 2004.

               Plot the data in your calculator, where x represents the number of years "after" 2004.

When it says "since", 2004(which is x) will be equal to 0 and for "after", 2004 will be equal to 1?

Is it always since for 0 and after for 1?

 

 

Answer 1

My view is that t = 0 occurs at the moment the clock registers midnight between Dec 31, 2003, and Jan 1, 2004. That's the beginning of 2004.

 

If you call 2004 Year 1, then the beginning of Year 1 is t = 0, the end of Year 1 is t = 1 yr, and the duration of Year 1 is 1 year – 0 = 1 year.

 

This is of course what we do with our calendar. We are currently in Year 2014 that began at t = 2013 years from the designated beginning of the year count, will end at t = 2014 years from the designated beginning of the year count, and has duration 1 year.

 

Note that although there is a t = 0 in our calendar system, there is no Year 0.

Answer 2

It's common in financially-related topics to start something at the beginning of the year and call it year 0, hence the beginning of 2004 is year 0, then the beginning of 2005 is year 1, etc.  So what you said makes total sense from that standpoint.

 

They also may mean the end of 2005 is year 1, as that's 1 year since 2004 has ended, i.e. how many years have gone by since 2004 was over. 

 

Either way your interpretation would work, and I think that's the easiest way to see it.  I'd love to see others concur on this though, because I could see a case for calling 2004 year 1.