It is possible to fail the defence of a doctoral thesis. Candidates must present and defend their findings before a panel of experts during the crucial defence phase. The candidate may lose the defence if the committee discovers serious errors in the technique, research, or conclusions, or if the candidate does not show that they have a thorough knowledge of the work. The committee might occasionally permit changes and a re-defense. However, losing a defence typically means that the thesis needs to be significantly improved before it can be accepted. Success depends on having a solid, unique thesis and being well-prepared.