The series comes from the 'Current Population Survey (Household Survey)'
The source code is: LNS12032198
Source: US. Bureau of Labor Statistics
Release: Employment Situation
US. Bureau of Labor Statistics, Employment Level: Part-Time for Economic Reasons, Slack Work or Business Conditions, Nonagricultural Industries [LNS12032198], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/LNS12032198/, July 29, 2015.