1.12 We use the following assurance categories to indicate our assessment of the reported savings:
• Sufficient evidence. The calculations for the saving are clear, the evidence base is available, any assumptions made are realistic, measurement uses strong benchmarks (e.g. recent, actual cost data) and sufficient prudence has been exercised.
• Partial evidence. The saving has some uncertainty or the evidence base is not clear. For example if there is no recent or actual cost information to draw on, a best estimate of future avoided cost has been used.
• Insufficient evidence. The saving is not supported by documentary evidence, or the estimates or assumptions are unrealistic or contested.