In the closing part of his mini-series on OSS business models, Carlo Daffara concludes that property and efficiency form the basis of all the business models he has analysed - where property is 'anything that may be transferred to another entity through a contract or legal transaction' and efficiency is the 'ability to perform an action at a lower cost'. 'There is no ideal model,' he believes, 'but a spectrum of possible models [between property and efficiency], and companies should adapt themselves to changing market conditions and adapt their model as well.'