In case you're interested in this subject at all, here's a good, recent, but tedious (i.e. highly wonkish) econ. paper that discusses two types of measures of potential output (GDP).http://research.stlouisfed.org/publications/review/09/07/Basu.pdf  

My particular interest in this (and other papers on the subject) is that they show historic measures of productivity & often by separate sources of it.... and of course, more importantly  describe the input measures & assumptions are used to derive the measure of productivity.  

 

There are two aspects of my interest --- 1)  If &/or how productivity effects / effected divergence of median family income from GDP/capita in the late '70's, and 2) do the models used to describe past, current, &/or future growth of potential output take into account or consider implications of those factors that relate to exponential productivity growth rates.  The latter having to do with whether these models are consistent with ability to consider forces that drive / create productivity at exponential rates.  This relates to my general observation that productivity growth rates which exceed population growth (workforce growth) must necessarily result in a corresponding exponential decay of labor required to sustain economic growth. ... ultimately leading to a near labor-less economic society.