whom profits and decision making are not necessarily shared equally. Workers also often undergo a trial or screening period (such as three or six months) before being allowed to have full voting rights. Participation is based on one vote per worker-owner, regardless of the number of shares or equity owned by each worker-owner. Voting rights are not tied to investment or patronage in the workers' co-operative, and only worker-owners can vote on decisions that affect them. In practice, worker co-operatives have to accommodate a range of interests to survive and have experimented with different voice and voting arrangements to accommodate the interests of trade unions, local authorities, those who have invested proportionately more labor, or through attempts to mix individual and collective forms of worker-ownership and control. As noted by theorists and practitioners alike, the importance of capital should be subordinated to labor in workers' cooperatives. Indeed, Adams et al. see workers' cooperatives as "labor-ist" rather than "capital-ist": "Labor is the hiring factor, therefore the voting and property rights are assigned to the people who do the work and not to capital, even though the worker-members supply capital through membership fees and retained earnings...Any profit or loss after normal operating expenses is assigned to members on the basis of their labor contribution." Nevertheless, recent developments in the co-operative movement have started to shift thinking more clearly towards multi-stakeholder perspectives. This has resulted in repeated attempts to develop model rules that differentiate control rights from investment and profit-sharing rights. Workers' co-operatives have often been seen as an alternative or "third way" to the domination of labor by either capital or the state (see below for a comparison). Co-operatives traditionally combine social benefit interests with capitalistic property-right interests. Co-operatives achieve a mix of social and capital purposes by democratically governing distribution questions by and between equal controlling members. Democratic oversight of decisions to equitably distribute assets and other benefits means capital ownership is arranged in a way for social benefit inside the organization. External societal benefit is also encouraged by incorporating the operating-principle of cooperation between co-operatives. In short, workers' co-operatives are organized to serve the needs of worker-owners by generating benefits (which may or may not be profits) for the worker-owners rather than external investors. This worker-driven orientation makes them fundamentally different from other corporations. Additional cooperative structural characteristics and guiding principles further distinguish them from other business models. For example,