Handbook of Methods Job Openings and Labor Turnover Survey Design

The Job Openings and Labor Turnover Survey (JOLTS) sample design is a probability-based stratified random sample. The basic sample unit is an establishment at a single physical location. Most sampled establishments remain in the survey for 36 months and, after completing time in sample, are not sampled again for at least 3 years.

The sample of establishments is stratified by ownership (private or public), Census region (Northeast, Midwest, South, and West), industry sector, and size class. Establishment level industry codes are assigned using the North American Industry Classification System (NAICS). The exhibit below shows the subsectors in the private sector and the subsectors in the public sector that are used for stratification.

There are six employment size classes: 1–9; 10–49; 50–249; 250–999; 1,000–4,999; and 5,000 or more. All establishments with 5,000 or more employees are included in the sample with virtual certainty and remain in the sample as long the employment count remains at or above 5,000 employees.

The sample is divided into 36 noncertainty panels and a single certainty panel. Each month, a new noncertainty panel is rolled into the sample while an old noncertainty panel is rolled out of the sample. This approach maintains 36 active noncertainty panels plus the certainty panel. Noncertainty sample units are requested to provide data for 36 months.

JOLTS sample units (noncertainties) are allocated to the various strata using a standard Neyman allocation formula:

 n h = n N h S h ∑ N h S h

where,

n h is the number of units assigned to stratum h

n is the number of sample units to be allocated

N h is the number of population elements in stratum h

S h is the standard deviation of the population in stratum h

This formula assigns sample units to each stratum based on the number of frame units in each stratum and the standard deviation within the stratum relative to other strata. The standard deviation of the population is approximated based on the frame employment of the strata. That is, strata with largerN h or larger standard deviation S hget more sample relative to those with smaller N h orS h .

Each year, a new 12-panel sample is selected. At the time of the annual sample selection, not all of the panels from previously selected samples have rolled out of the sample. Therefore, there are panels from multiple samples active in the current sample at any given time. Each year, the older panels are updated with respect to current strata characteristics (industry, size, and region); updating also includes the removal of establishments that go out of business. The sampling weights of establishments to be used in the survey are recomputed to reflect the current sample population, and post-stratification is done to represent the updated age structure of the frame. In other words, each sample unit is re-weighted.

To ensure that newly opened establishments (also called births) are represented in the sample as soon as possible, a sample of birth units is selected from the updated frame every quarter. Quarterly birth samples were first implemented in April 2009. The birth units are selected from establishments that first reported positive employment during the current quarter and belong to JOLTS size class 1–9, 10–49, or 50–249. The birth units are sampled from strata defined by age, industry, and size.

Each stratum’s birth sample size is calculated by dividing the number of births in the stratum by the stratum reweight. If the stratum has three or fewer birth units, then all the birth units in the stratum are selected. Weights are assigned to the birth sample units by dividing the number of total birth units in the sample strata by the actual number of birth units selected for that strata. All the sampled birth units are then distributed evenly into three sample panels that are rolled into the sample over the quarter.

The JOLTS program and the Current Employment Statistics (CES) program use a sample that is based on the Quarterly Census of Employment and Wages (QCEW). The JOLTS program uses the sample frame developed by the CES program for which all businesses are in scope. Therefore, bias studies are not conducted by JOLTS as the bias would not be dependent on the JOLTS sample but upon the CES sample selected from the QCEW. Because JOLTS uses the CES frame, the coverage rates never fall below 85 percent. If this did occur, JOLTS would conduct a bias study; however, because the CES and QCEW have high percentage coverage, this has not been necessary.