I asked the folks at O*NET what the differences are between these three career/job information resources from the federal government, because they all seem to overlap in one way or another, and yet, they don't. This is their reply:
The Occupational Information Network (O*NET) provides information about the characteristics of occupations and the people who work in them. We collect occupational data from a national random sample of incumbents. The bulk of the data collected and published by the O*NET project is collected using a survey instrument (Questionnaires) completed by either job incumbents or occupational experts. More detailed information about our data collection process can be found on the O*NET resource web site at http://www.onetcenter.org/ombclearance.html in the 2024 OMB Clearance Package. The Questionnaires contain the descriptors and importance and level rating items. An explanation of the descriptors contained in the O*NET database can be found in O*NET Content Model section of our resource web site.
America’s Career InfoNet is transitioning to CareerOneStop’s Toolkit. Visit the Toolkit for the complete collection of CareerOneStop’s tools to research career information, training, or jobs. The Toolkit provides some of the tools needed to research careers, find training, or search for jobs. CareerOneStop is the flagship career, training, and job search website for the U.S. Department of Labor. The website serves job seekers, businesses, students, and career advisors with a variety of free online tools, information and resources.
The Occupational Outlook Handbook (OOH) is a career resource offering information on the hundreds of occupations that provide most of jobs in the United States. Each occupational profile describes the typical duties performed by the occupation, the work environment of that occupation, the typical education and training needed to enter the occupation, the median pay for workers in the occupation, and the job outlook over the coming decade for that occupation. Each profile is in a standard format that makes it easy to compare occupations, such as by projected employment change. The Occupational Outlook Handbook crosswalk is developed and maintained by the Bureau of Labor Statistics. For more information on the OOH see: OOH FAQ's.