The employment-population ratio is the ratio of employment* to population. Unlike the unemployment rate, it shows the effects of discouraged workers leaving the labor force. The unemployment rate will go down as some workers get discouraged and are no longer counted as part of the labor force, since the unemployment rate is the ratio of workers counted as unemployed to the total number counted as being in the labor force.
This phenomenon in the unemployment rate has worked to the great benefit of Barack Obama by showing a decline in unemployment from near 10% to 8.2% over the last two years. Thus, Obama claims that the economy is improving. But the employment to population ratio underscores the reality that the unemployment rate hides. The Great Recession has not been followed by a Great Recovery, as deep recessions in the past always have been. This time the Great Recession has been followed by a Great Stagnation.
The way out of this is regime change in November.
*excluding government workers