Star formation rate as a function of [C ii] luminosity for different rings in the Galaxy, the LMC, the galaxies studied by de Looze et al. (2011), and for individual Galactic PDRs. The [C ii] luminosity of the LMC is taken from Rubin et al. (2009) and the SFR from Harris & Zaritsky (2009). The Galactic PDR data points include Orion (L_{[ CII ]} from Stacey et al. 1993, and SFR from Lada et al. 2010), M17 (L_{[ CII ]} from Stacey et al. 1991, and SFR from Lada et al. 2010), Rosette (L_{[ CII ]} from Schneider et al. 1998 and SFR from Chomiuk & Povich 2011), and Carina (L_{[ CII ]} from Brooks et al. 2003 and SFR from Chomiuk & Povich 2011). The [C ii] luminosities and SFRs for this sample are strongly correlated over 6 orders of magnitude.