Productivity is an economic identity with political interpretations that change over time.
(Adding identity at the margin occupies space over time.)
A lot of people who thought, for example, a guaranteed minimum income is an absolute violation of natural law (advancing no incentive to be productive) now say it is imperative for reducing emergent, financial crises in a TBTF proportion. (The change, in other words, is to conserve the distributive value of maintaining consolidation of the risk.)
Capitalism works to maximize labor value by adding yield (productivity) with less labor. This added identity (occupying space over time) is a highly creative attribute, adding properties at the margin that naturally gain more and more productivity (and not just per worker, but also per capita, effectively measuring the space occupied by “saving” time, effectively measuring the expected velocity of change at an accelerating rate of interest).
The way these “gains” distribute economically has political attributes (emergent properties in a crisis proportion). Nevertheless, the gains naturally exist as useful, economic value, unambiguously measured by doing more work with less human effort, which “produces” a measurable surplus value (having emergent properties). Classical economists called the surplus (the added identity) “capital” for reinvestment (expanding the supply at the margin). Today we use “capital reserves” to control for financial risk, gaining productivity with less human effort, accumulating capital (the surplus value) measured by unemployment. The result is a free-market price for labor, but since we allow industry and markets to consolidate, the prices consumers have to pay for the supply added is less and less a free-market price. The differential is the emergent property of the crisis proportion in the form of “productivity gains” (rising income inequality and rising debt to equity, measuring the emergency attributes of managing the risk in a TBTF dimension).
If productivity is the measurable existence of the profit motive, its identity is well established in the form of price discovery. Use of the Epipen, for example, discovered that a “natural monopoly” price also has a natural political identity (its fundamental, free-market, on-demand identity) that is not really disconnected from its economic attributes.
The real value of the Epipen is the technology that saves time. Users realize the value in the form of the price, and in the case of the monopoly price the value is discovered in the form of not being able to afford to buy it; or in the form of declining, real income, which is the measurable “income inequality” that was at the center of the Sanders campaign, naturally acting to draw big crowds, occupying a lot of space, in a short amount of time, created on demand.