Best approach for minimizing error for a given year when using overlapping 5-year data?

Hi Folks,

This is my first post and day on this forum.  I couldn't find the answer to this question, but if there is a good thread which exists already, please point me in that direction.

I am conducting an analysis where my geographic region is at the county level.  As such, I would like to use the 5-year data.

However, I need to run a calculation for a single year.  For example,  I need to run a calculation in Suffolks County, NY for 2010.  There are several 5 year samples (2006-2010,2007-2011...2010-2014) which overlap and include 2010.

What is the optimal approach, in terms of minimizing error, of dealing with this?  How do I combine, if at all, the different multi-year datasets to find the best figure to use.

thanks,
Eric