22 enterprise’s leverage over the entity concerned, how crucial the relationship is to the enterprise, the severity of the abuse, and whether terminating the relationship with the entity itself would have adverse human rights consequences. The more complex the situation and its implications for human rights, the stronger is the case for the enterprise to draw on independent expert advice in deciding how to respond. If the business enterprise has leverage to prevent or mitigate the adverse impact, it should exercise it. And if it lacks leverage there may be ways for the enterprise to increase it. Leverage may be increased by, for example, offering capacity-building or other incentives to the related entity, or collaborating with other actors. There are situations in which the enterprise lacks the leverage to prevent or mitigate adverse impacts and is unable to increase its leverage. Here, the enterprise should consider ending the relationship, taking into account credible assessments of potential adverse human rights impacts of doing so. Where the relationship is “crucial” to the enterprise, ending it raises further challenges. A relationship could be deemed as crucial if it provides a product or service that is essential to the enterprise’s business, and for which no reasonable alternative source exists. Here the severity of the adverse human rights impact must also be considered: the more severe the abuse, the more quickly the enterprise will need to see change before it takes a decision on whether it should end the relationship. In any case, for as long as the abuse continues and the enterprise remains in the relationship, it should be able to demonstrate its own ongoing efforts to mitigate the impact and be prepared to accept any consequences – reputational, financial or legal – of the continuing connection. 20. In order to verify whether adverse human rights impacts are being addressed, business enterprises should track the effectiveness of their response. Tracking should: (a) Be based on appropriate qualitative and quantitative indicators; (b)  Draw on feedback from both internal and external sources, including affected stakeholders.