by Calculated Risk on 3/04/2013 08:53:00 AM

From Fed Vice Chair Janet Yellen: Challenges Confronting Monetary Policy. A few excerpts on asset purchases and what a "Substantial Improvement in the Outlook for the Labor Market" means:

The first imperative will be to judge what constitutes a substantial improvement in the outlook for the labor market. Federal Reserve research concludes that the unemployment rate is probably the best single indicator of current labor market conditions. In addition, it is a good predictor of future labor market developments. Since 1978, periods during which the unemployment rate declined 1/2 percentage point or more over two quarters were followed by further declines over the subsequent two quarters about 75 percent of the time.

That said, the unemployment rate also has its limitations. As I noted before, the unemployment rate may decline for reasons other than improved labor demand, such as when workers become discouraged and drop out of the labor force. In addition, while movements in the rate tend to be fairly persistent, recent history provides several cases in which the unemployment rate fell substantially and then stabilized at still-elevated levels. For example, between the fourth quarter of 2010 and the first quarter of 2011, the unemployment rate fell 1/2 percentage point but was then little changed over the next two quarters. Similarly, the unemployment rate fell 3/4 percentage point between the third quarter of 2011 and the first quarter of 2012, only to level off over the subsequent spring and summer.

To judge whether there has been a substantial improvement in the outlook for the labor market, I therefore expect to consider additional labor market indicators along with the overall outlook for economic growth. For example, the pace of payroll employment growth is highly correlated with a diverse set of labor market indicators, and a decline in unemployment is more likely to signal genuine improvement in the labor market when it is combined with a healthy pace of job gains.

The payroll employment data, however, also have shortcomings. In particular, they are subject to substantial revision. When the Labor Department released its annual benchmarking of the establishment survey data last month, it revised up its estimate of employment in December 2012 by 647,000.

In addition, I am likely to supplement the data on employment and unemployment with measures of gross job flows, such as job loss and hiring, which describe the underlying dynamics of the labor market. For instance, layoffs and discharges as a share of total employment have already returned to their pre-recession level, while the hiring rate remains depressed. Therefore, going forward, I would look for an increase in the rate of hiring. Similarly, a pickup in the quit rate, which also remains at a low level, would signal that workers perceive that their chances to be rehired are good--in other words, that labor demand has strengthened.

I also intend to consider my forecast of the overall pace of spending and growth in the economy. A decline in unemployment, when it is not accompanied by sufficiently strong growth, may not indicate a substantial improvement in the labor market outlook. Similarly, a convincing pickup in growth that is expected to be sustained could prompt a determination that the outlook for the labor market had substantially improved even absent any substantial decline at that point in the unemployment rate.
emphasis added

CR Notes: Defining a "substantial improvement" is helpful in trying to determine when the Fed when end the asset purchase program.  Obviously the program will continue for some time ...