# Why do estimates of potential GPD made at different origins differ?

I am stuck on a diagram that shows the development of GDP over time period from '04 to '16. We have 4 graphs; actual GPD, and estimates of potential GDP made in '07, '10 and '15.

Now to the actual question. I am trying to understand why the different estimates for potential GDP differs in the earlier years. Why is the estimate made in 2015, when look ex. at the years 04 - 07, different than the estimate made in 2010.

• Potential GDP changes over time. If you estimate potential GDP in different years you will get different numbers. What is puzzling about that? Oct 24 at 9:58
• @csilvia I guess the OP wants to know about the sort of information that is used for estimation; sort of an introduction to forecasting. Oct 24 at 11:59
• @Giskard idk, the post says its the same graph with different time periods so difference should be in different data Oct 24 at 14:14
• Yes, the forecast for '16 depends on data from e.g.; '15, which is also forecasted in prior time periods, but is available (or can be more accurately estimated) in '15. An answer would probably expound on this concept. Oct 24 at 14:29