One of the key reasons why CBT is so effective is because of its interactive nature. This is known as collaborative empiricism; the patient and therapist work together in targeting problems and changing negative mindsets. This means that patients play an active role in improving their mental health which is a key element that distinguishes CBT from other treatments. Therapists encourage patients to be active by setting them tasks. This may be noting down positive moments throughout their day or producing a list of things to complete. CBT combines cognitive and behavioural methods to maximise its effect. Therapists often set their patients homework which challenge their irrational beliefs. When patients feel down because of these beliefs, the therapist can produce this as evidence. An example of a behavioural method is that therapists help their patients to collect evidence that challenges the use of their avoidance behaviours. The techniques aim to prepare patient with the skills they need to target their problems independently in the future. 