The series comes from the 'Current Population Survey (Household Survey)'
The source code is: LNS12032194
Source: US. Bureau of Labor Statistics
Release: Employment Situation
US. Bureau of Labor Statistics, Employment Level: Part-Time for Economic Reasons, All Industries [LNS12032194], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/LNS12032194/, September 4, 2015.