In April 2017, 1.5 million people were marginally attached to the labor force, down by 181,000 from April 2016, according to new Bureau of Labor Statistics numbers. These individuals were not in the labor force, wanted and were available for work, and had looked for a job sometime in the prior 12 months. They were not counted as unemployed because they had not searched for work in the 4 weeks preceding the survey. Among the marginally attached in April 2017, 455,000 were discouraged workers, a decrease of 113,000 from April 2016. Discouraged workers are people not currently looking for work because they believe no jobs are available for them. Other persons marginally attached to the labor forces describes people who had not searched for work in 4 weeks preceding the survey for reasons such as school attendance or family responsibilities.
Additional data here.