There are at least two types of<unk> s, non-response and underpayment / non-payment.<unk> s are separate from formal<unk> nials. Non-response<unk> nials If an insurer does not respond in a timely manner to a claim or request to authorize a service, it may be challenged in court as a<unk>  of service, though other<unk>  of the case will be relevant. In workers' compensation cases,<unk>  of coverage due to non-response can occur if an insurer fails to respond in writing within a certain time. In the United States, particularly in health insurance markets, there are often state requirements that insurers do not engage in<unk> s by non-response or<unk> layed responses. In Colorado for example, a response is due to a provider and enrollee within five business days for non-urgent and two business days for urgent health care requests for service authorization. Underpayment and non-payment<unk> nials<unk> s can occur because of underpayment or non-payment, even if a written approval is also provided. This occurs if the reimbursement approved by the claim is insufficient for the enrollee, worker or patient to receive needed and approved services. In some cases, this kind of<unk>  occurs because of a technical or claims processing problem. In other cases, it can be a<unk> liberate part of a carrier's utilization management strategy. Legal cases have been brought against public and private insurers when rates are set too low to provide sufficient access. An example of<unk>  by underpayment would be if a worker receives an approval for mental health treatment, but his or her insurer has set a rate so low that it does not have any mental health service providers in its network. An example of<unk>  by non-payment would be if the carrier "approves" treatment but does not authorize payment for the approved service. Inadequate payment that prevents a person from obtaining a necessary service from at least one capable provider, whether intentional or incidental, may be referred to as<unk> , effective<unk> nial, or functional<unk> nial.
De facto denial
Informal coercion
Avolition
Capital punishment
Casualty 
Co-option 
Foreclosure 
Right-to-try law