We provide critical notes to the paper by Kallis et al. (2013) on monetary valuation. We evaluate the four criteria they propose for assessing valuation studies. We argue that no clear distinction is made between monetary valuation and pricing instruments. The selected criteria are more relevant to assessing policy than monetary valuation. The examples provided are not representative of the diversity of valuation studies encountered in the literature. Moreover, no clear examples are provided of where valuation and associated cost–benefit analysis of environmental policy go wrong. We plea for a more fair, constructive and consistent criticism of all “valuation languages” and offer relevant issues for consideration. •We provide critical notes to the paper by Kallis et al. (2013) on monetary valuation.•We evaluate the four criteria they propose for assessing valuation studies.•No clear distinction is made between monetary valuation and pricing instruments.•No clear examples are provided of where monetary valuation goes wrong.•We plea for a fair, constructive and consistent criticism of all valuation languages.