why was the economy 50% less productive in 1968 then it is today?

Answer 1

Improvements in technology especially the automation of many activities, increased the productively of workers.

The change in the labor force. Today people delay starting work to obtain more education, and old people retire, so the workers are more educated and in their prime productive years. Women joining the work force has kept fraction of the adult population who works about the same.

To a lesser extent trade, outsourcing some of our least productive jobs in ecahange for jobs where we have a comparitive advantage. This has been only a small portion so far but is of growing importance. However the increase in trade with poor countries is forcing our low skilled workers to compete with the low wage labor in other countries. As a result most of the return on productivity gains have gone to the well educated high income earners, and people in thoes occupations where we have the comparitive advantage such as finance.

Answer 2

Production is the sum whole of everything produced. If population goes up, and supply is proportionately related to population, there will be an increase in production. Discovery leads to more production (especially with technology and machinery). Knowledge (aka human capital) makes people work more effeciently, therefore more is produced. Foreign demand is also up from it was in the 60s, so we supply more to meet the demand.

Answer 3

Innovation. As technologies are developed, we increase the unit-per-employee ratio, the measure of productivity.

Answer 4

Different methods of measuring "productivity."

Back then farm labor, notoriously inefficient, was included in the general measure of productivity. Now that segment is excluded so we can congratulate ourselves on being more efficient, and claim we got that way through technology.

we didn't. We got that way by manipulating the data.