Lobbying can have a profound impact on the outcome of public policies and, in turn, on well-being and living standards in societies. By sharing expertise, legitimate needs and evidence, interest groups can provide governments with valuable insights and data on which to base public policies. This can help policy makers understand options and trade-offs, and can lead, ultimately, to better policies. Lobbying to strengthen environmental standards, improve road safety or increase childcare services, for example, can benefit society as a whole. Nonetheless, the abuse of lobbying practices – such as the monopoly of influence by special interest groups, undue influence through covert or deceptive evidence, or the manipulation of public opinion – can result in suboptimal policies and outcomes. An analysis of 300 academic studies showed that such abuse has led, for example, to negative health outcomes, inaction on climate policies, excessive regulation to protect incumbents, or insufficient regulation to correct market failures or distortions. In addition, the abuse of lobbying practices undermines citizens’ trust in democratic processes.