Specific star formation rate as a function of the stellar mass for a set of redshifts (the redshift is increasing clockwise). This quantity can be seen as the inverse of the stellar mass doubling time. The higher the value, the more intense the star formation activity. We compare the models (colour−coded) with observational data from Dunne et al. (2009), Karim et al. (2011), Gonzalez et al. (2012), Reddy et al. (2012), and Béthermin et al. (2012). For most observational data points, errors are smaller than the size of the symbol.