A mental capacity test is how we work out a person’s ability to make a specific decision. Different decisions require you to understand different things, we call this ‘The threshold of understanding’. The threshold of understanding for different decisions is established either through case law (for example in the case of making a Will its Banks v Goodfellow) or through the Mental Capacity Act (2005).
The use of the word test is often misleading – a mental capacity assessment is much more about having a conversation with someone. In fact, we do our very best not to make it feel like a test as we want to ensure the person is comfortable and feels able to answer without pressure.