In this comment, we discuss the arguments raised in two recent papers (Costley 2016 Nucl. Fusion 56 066003, Costley et al 2015 Nucl. Fusion 55 033001) on the claimed size independence of fusion power, triple product and fusion gain in tokamak reactors, and we show that all these three quantities actually do depend on the size of the tokamak, when distinguishing between independent input parameters (design parameters) and output quantities, and when taking into account technological limitations.