In contrast, in an NIS or systems approach, the role of government is to correct systemic failures, which might include market failures, but can also include weak relationships between agents or institutions which are difficult to capture in traditional economic models. A systemic analysis also focuses on how changing incentives in one area negatively affect incentives in others. Knowledge in its pure form is a public good, insofar as it is available to everyone and its use by one person does not limit its use by others.