AGRICULTURAL SAFETY
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National Agricultural Workers Survey (NAWS)
Technical Information
DATA SOURCE & CASE DEFINITIONS
Data Source
NAWS is an on-going survey conducted by the US Department of Labor, Employment and Training Administration (USDOL/ETA). Through an interagency agreement between the National Institute for Occupational Safety and Health (NIOSH) and the USDOL/ETA, NIOSH provided funding for USDOL/ETA to collect NAWS data on hired crop worker injuries occurring on US crop operations. Hired crop worker injury data were collected through face-to-face interviews for the years 1999, 2002-2004, and 2008-2010. For more information about the general NAWS data system, go to USDOL/ETA- NAWS.
Sample Design
NAWS is an employer based, multi-stage probability sample survey that takes into account the seasonal and regional fluctuations in the level of farm employment. Seasonal fluctuations are accounted for by three interviewing cycles to incorporate nearly year around interviewing. All states are included except Alaska and Hawaii. The NAWS sample is stratified by 12 regions (see NAWS Region). Within each region, farm labor areas consisting of counties (or several smaller counties aggregated) are selected from which a simple random sample of agricultural employers (growers) is selected. The end stage of the sampling process is a random sample of hired crop workers at each farm based on established protocol. Interviews are conducted in a location of the crop worker’s choice. The use of an employer-based sample (rather than a household-based sample) increases the likelihood that migrant and seasonal workers will be interviewed. For a detailed description of the sampling methodology, go to USDOL/ETA- NAWS Methods.
Case Definitions
Hired crop worker – An eligible hired crop worker is defined as anyone 14 years and older who works on any type of crop farm; and has worked in the last 15 days for at least one day for 4 hours or more for the current employer. The crop worker’s documentation status is not an eligibility consideration for inclusion in the survey.
Crop farm – Crop farms are defined as those farms classified in the North American Industrial Classification System (NAICS) as Crop Production (NAICS code 111) or as Support Activities for Crop Production (NAICS code 1151). NAICS 111 comprises establishments such as farms, orchards, groves, greenhouses, and nurseries that are primarily engaged in growing crops, plants, vines, or trees and their seeds. NAICS 1151 includes establishments primarily engaged in providing support activities for growing crops, including labor supply, aerial dusting or spraying, cotton ginning, cultivating services, farm management services, planting crops, and vineyard cultivation services. For more information about farms included in NAWS, go to USDOL/ETA- NAWS Sampling universe.
Occupational Injury – An injury at work is one that resulted in a hired crop worker meeting at least one of the following criteria: (1) Unable to work for at least 4 hours; or (2) Unable to work as hard as normal for at least 4 hours or being assigned a different job task that was easier because of the injury; or (3) Received any type of first aid or medical treatment at a clinic or from a nurse or doctor; or (4) Used strong medicine (excluding aspirin, Tylenol, or ibuprofen) in order to keep working.
STATISTICAL INFORMATION
Demographic percentage distributions
NAWS is designed to produce national percentage distributions for hired crop workers 14 years of age and older in the US by various demographic characteristics. Demographic characteristics include age, sex, education, country of birth, years of farm work experience in the US, migrant status, and direct vs indirect employment status. Nationally weighted percentage distributions with 95% confidence intervals are available for two survey periods: 1999, 2002-2004 and 2008-2010.
Injury percentage distributions
NAWS is designed to produce national percentage distributions for hired crop workers 14 years of age and older in the US by various occupational injury characteristics. Occupational injury characteristics include age and sex of the injured worker, nature of the injury, source of injury, type of injury event, and the body part and nature of injury. Nationally weighted percentage distributions with 95% confidence intervals are available for two survey periods: 1999, 2002-2004 and 2008-2010.
Injury rates per 100 week-based FTE
Injury rates were calculated using employment estimates derived from NAWS demographic data and adjusted for weeks of farm work during the previous 12-months (as self-reported by the hired crop workers) and referred to as week-based full-time equivalents (FTEWB). One FTEWB was set equal to 50 weeks of farm work. The injury rates are presented per 100 FTEWB. All injury rates are nationally weighted estimates with 95% confidence intervals.
Confidence intervals
To account for the complex sample design during calculation of standard errors, SAS software Version 9.3 (SAS Institute, Cary, NC) Proc SurveyMeans and SurveyFreq procedures were utilized. All confidence intervals are calculated at the 95% level.
Statistical Weighting
Sampling and post-sampling weights are used in the NAWS to adjust the relative value of each interview so that population percentage distributions may be obtained from the sample. For these tables, the composite weight variable is used to generate unbiased estimates across multiple years to adjust for varying sample size per year and employment changes during seasonality. For a detailed report of the statistical weighting procedures, go to USDOL/ETA- NAWS Methods.
DATA ELEMENTS
Age
Age of the hired crop worker in years at the time of interview.
Sex
The distinction between male and female.
Body part
The part of the body or region of body that was injured.
Nature of injury
The type or nature of injury that occurred (e.g., burn, fracture, cut or laceration).
Farm work experience
The hired crop worker’s number of years of farm work experience in the US.
Non-migrant (settled) crop worker
A non-migrant or settled crop worker is one who does not travel more than 75 miles from a usual residence for farm work. For more detail about migrant and non-migrant classifications, go to USDOL/ETA- NAWS Chapter 1: Migrant types.
Migrant crop worker
A migrant crop worker is one who travels a distance of more than 75 miles from a usual residence to a farm job during the past year. Migrant crop workers are further divided into shuttle migrant workers and follow-the-crop migrant workers. For more detail about migrant crop workers, go to USDOL/ETA- NAWS Chapter 1: Migrant types.
Shuttle migrant worker
A shuttle migrant worker is one who travels a distance of more than 75 miles from a usual residence to a single farm location, and works within a 75-mile radius of that location. For more detail about shuttle migrant workers, go to USDOL/ETA- NAWS Chapter 1: Migrant types.
Follow-the-crop migrant worker
A follow-the-crop migrant worker is one who travels a distance of more than 75 miles from a usual residence to multiple farm locations. Follow-the-crop migrants might or might not do US farm work at their home base. For more detail about follow-the-crop migrant workers, go to USDOL/ETA- NAWS Chapter 1: Migrant types.
Direct hire employment status
Hired directly by the farm operator.
Indirect hire employment status
Hired indirectly to work on a farm through a labor contractor.
Education
Years of formal education including both the US and abroad.
Country of origin
The hired crop worker’s country of birth.
OIICS Event Code
The manner in which the injury was produced or inflicted as coded in the Bureau of Labor Statistics Occupational Injury and Illness Classification System (OIICS version 2.01). The event or exposure is classified in a hierarchical structure with general divisions: violence and other injuries by persons or animals; transportation incidents; fires and explosions; falls, slips, trips; exposure to harmful substances or environments; contact with objects and equipment; overexertion and bodily reaction; and non-classifiable. Each case is coded to the most significant level of detail permitted by using the information abstracted from a narrative.
OIICS Source Code
The object, substance, bodily motion, or exposure which directly produced or inflicted the injury or illness as coded in the Bureau of Labor Statistics Occupational Injury and Illness Classification System (OIICS version 2.01). The source is classified in a hierarchical structure with general divisions: chemicals and chemical products; containers, furniture, and fixtures; machinery; parts and materials; persons, plants, animals, and minerals; structures and surfaces; tools, instruments, and equipment; vehicles; and non-classifiable.
DATA LIMITATIONS
Disclaimer
Although NIOSH extends considerable effort to insure reasonable quality for NAWS results, there are no warranties expressed or implied. The objective of NAWS is to provide public access to demographic and injury percentage distributions, and injury rate estimates for hired crop workers on US farms for use in farm safety and injury prevention activities where understanding the statistical distributions of these characteristics are important. Use of these data for other purposes should be done with caution.
Limitations
There are several limitations to the results from NAWS including eligibility criteria for workers being selected for an interview, a 12-month recall period for injury, and non-response bias. Also, it was not possible to verify the accuracy or completeness of the self-reported survey responses. Additional details of NAWS limitations are available in Steege et al. (2009), Wang et al. (2011), Tonozzi and Layne (2016) and USDOL/ETA- NAWS Data limitations.
- Page last reviewed: May 12, 2017
- Page last updated: May 12, 2017
- Content source:
- National Institute for Occupational Safety and Health Division of Safety Research