‘Optimism bias’ refers to the tendency for project appraisers to be impractical and unrealistic, which can lead to a failure to deliver, delays, poor service quality or a need for later funding injections.24 The prevalence of optimism bias in government has been highlighted before. For example, the Shared Service centres initiative fell far short of the planned savings and failed to achieve value for money and, more recently, we reported on the Ministry of Defence’s Equipment Plan for 2019–20...

‘Optimism bias’ refers to the tendency for project appraisers to be impractical and unrealistic, which can lead to a failure to deliver, delays, poor service quality or a need for later funding injections.24 The prevalence of optimism bias in government has been highlighted before. For example, the Shared Service centres initiative fell far short of the planned savings and failed to achieve value for money and, more recently, we reported on the Ministry of Defence’s Equipment Plan for 2019–2029 including unrealistic expectations for £4.7 billion of efficiency savings, a figure for which it had no plans.25 Type: conclusion | Number: 10 | Response status: not_addressed Government response: 3. PAC conclusion: Previous efficiency programmes have over-promised and under- delivered. 3: PAC recommendation: HM Treasury need to ensure plans are subject to adequate challenge, testing the realism of departments’ expected savings, and considering the use of pilots where appropriate. 3.1 The gov