Monday, July 15, 2013

Why The US Bureau Of Labor Statistics Makes Revisions To Its Employment Numbers In The Two Months Following Release

From The Bureau of Labor Statistics, Beyond the Numbers, "Why are there revisions to the jobs numbers?" by Thomas Nardone, Kenneth Robertson, and Julie Hatch Maxfield:
At the beginning of each month, the Bureau of Labor Statistics (BLS) reports the change in payroll employment for the previous month.
The estimate of employment change is based on a monthly survey of about 560,000 worksites, selected to represent the millions of businesses throughout the country. (For simplicity, we will refer to worksites as businesses even though many individual businesses provide data for multiple worksites.) In the survey sample, businesses report the total number of people who worked or received pay during the pay period that includes the 12th of the month. Although BLS uses a variety of methods to gather these reports as quickly as possible, many businesses do not have their payroll data ready to report by the scheduled date that BLS initially releases the data. In 2012, for example, the average collection rate at the time of the initial release was 73.1 percent.

The initial estimate of job change for a month is based on the growth or loss of jobs at the businesses that have reported their data. Generally, BLS assumes that the employment situation at businesses that had reported is representative of the situation at those that had not yet reported. BLS continues to collect outstanding reports from the businesses in the sample as it prepares a second and then a third estimate for the month. With each subsequent estimate, more businesses have provided their information. In 2012, the average collection rate at the time of the third estimate for a month was 94.6 percent. (See chart 1.)
Source:  Bureau of Labor Statistics

No comments:

Post a Comment