Every time a national unemployment report comes out, I tweet the many details from @politicalmath. Frequently I get a lot of the same questions, so I thought I’d jot down a quick summary on unemployment reports and numbers and where they come from.
There are 2 kinds of employment numbers, summarized here:
- Establishment Data (Current Employment Statistics or CES) – this survey covers 400,000 businesses and counts the number of payroll positions that are filled.
- Household Data (Current Population Survey or CPS) – this survey covers 60,000 households and counts the number of people who are employed and unemployed.
When an employment report comes out from the Bureau of Labor Statistics (BLS), they usually report:
- The unemployment rate, which is calculated using household data
- The number of jobs added, which comes from the establishment data
Sometimes this data can seem contradictory. For example, between March and June 2011, we gained 290,000 jobs but the unemployment rate went up .4% (from 8.8% to 9.2%).
There can be a couple reasons for this. The first one is that, the “jobs added” number comes from subtracting last month’s establishment jobs number from this month’s establishment jobs number, but we never use either of those numbers to calculate the unemployment data.
Because the essence of the establishment jobs number is asking employers: “How many people work for you?” It gives a nice accurate number, but it doesn’t tell us anything about how many people don’t work for them. We don’t have any number on the unemployed, only a number for jobs.
For unemployment, we have to go to individuals and ask them: “Are you employed or unemployed?” Then we take the unemployed number and divide it by the total number of people who are in the labor force, which counts both the employed and the unemployed.
But even the differences between the establishment jobs number and the household jobs number can be big. According to the household jobs number (which is supposed to exclude farm workers and the self-employed), we had 139.6 million jobs in August 2011. According to the establishment jobs number, we had 131.1 million.
That’s a difference of 8.5 million jobs, and that kind pf spread is pretty normal. The variation changes a little month-to-month, but we could get a report of jobs created from the household number and jobs lost from the establishment number. In fact, we saw something similar in August where the household number said we gained 331,000 jobs, but the establishment number said we gained 0.
So why do we report the establishment number?
Because the establishment survey is so much larger, more reliable and gives more consistent results. In the graph below , we can see that even though the establishment data counts fewer jobs, it is a less erratic count.