Publication - Research and analysis

Supervised Bail in Scotland: Research on Use and Impact

Published: 29 Mar 2012

This report outlines findings on the use and impact of supervised bail in Scotland from a research project which included analysis of operational data, economic analysis, a workshop with bail workers, surveys of the judiciary and Procurators Fiscal, and interviews with people who have been on supervised bail.

Supervised Bail in Scotland: Research on Use and Impact
8 Costs and savings

8 Costs and savings

8.1 This section will outline a cost benefit analysis of supervised bail as an alternative to remand, making use of the data collected specifically for this evaluation, including data on supervised bail expenditure, as well as other relevant publicly available statistics.

Average Expenditure Per Case

8.2 Table 2 shows average expenditure per case using the financial data received from the operators. Seven of the twelve active schemes were able to provide financial details related specifically to bail supervision, while three schemes provided details of the more general criminal justice budget in which bail supervision was located, and Orkney Islands Council and Stirling Council were unable to provide either such information and are excluded from the analysis. All costs have been adjusted into constant 2009 prices using the most recent GDP Deflators.

8.3 These expenditure estimates may therefore be overstating the true expenditure on bail supervision as they include the 3 schemes with non-identifiable expenditure, but to what extent we are unsure.

Table 2 - Total Expenditure of Active Schemes

Year Allocated Budget (2009£) Actual Expenditure (2009£) Number of Cases Average Expenditure per case (2009£)
2006-07 661,029 794,022 599 1,326
2007-08 678,397 765,562 575 1,331
2008-09 799,117 832,780 520 1,602
2006-09 2,138,543 2,392,364 1,694 1,412

8.4 Over the three years total expenditure in real terms amounted to nearly £2.4 million, while nearly 1,700 bail supervision cases were dealt with. This resulted in an average expenditure per case of £1,412 across all active schemes over the three years. There were some substantial differences in the average expenditure per case across the different schemes, although these figures are not reported here.

Table 3 - Average Costs per Day

Scheme Average Expenditure per Case (2009£) Average Length (Days) Average Expenditure per Case per Day (2009£)
Scotland* 1,412 56 25

* 10 active schemes which provided financial details

8.5 Table 3 calculates the average cost per case per day for Scotland overall by dividing the average expenditure per case over the three years by the average length of cases in the different schemes. The average across Scotland is £25 per case per day.

Costs of Supervised Bail compared to Remand Costs

8.6 We can estimate the costs and savings associated with the programme by comparing the total expenditure on bail supervision with the reduction in prison numbers owing to the schemes.

8.7 This is done using two methods to give an upper and lower range:

  • First, by assuming that the average time each supervised bailee would have spent on remand would have been equal to the average length of a supervised bail case (Upper Limit Analysis),
  • Second, by assuming the length of time they would have spent on remand is equal to the average length spent on remand in general for all prisoners (Lower Limit Analysis). In reality the length spent on remand would lie somewhere in between.

8.8 It was estimated that over the past three years between 157 and 41 remand prison places could have been saved at any one time assuming upper and lower limit conditions respectively, equating to between 471 and 123 places over the course of three years.

8.9 When an accused spends time on remand, and then is given a custodial sentence, the time spent on remand counts as part of the custodial sentence. This is not the case for time spent on supervised bail. Therefore there will be no savings in prison costs for those individuals on supervised bail who went on to receive a custodial sentence16 . This applies in 22% of the supervised bail cases examined here, and the remand places saved are reduced by this amount in our analysis to reflect this. This results in a net saving of between 366 and 97 remand places over the three years.

8.10 Combining the remand prison places avoided with the average cost per prison place over the three years (adjusted for inflation) we can estimate the total costs which would have been incurred had the accused been on remand rather than bail, and hence the savings associated with bail supervision schemes.

Table 4 - Net Benefits

Period (2006-09) Remand Days Saved Average Cost per Remand Place (2009£) Number of Annual Equivalent Remand Places Prevented Saving on Remand Expenditure (2009£) Expenditure on Supervised Bail (2009£) Net Benefit (2009£) Benefits to Costs Ratio
Upper limit 56 43,191 469.5 20,278,116 2,392,364 17,885,752 8.5
Lower limit 37 124 5,364,322 2,391,928 2,972,394 2.2

8.11 For the past 3 years the reduction in remand places would result in a reduction of between £4 million and £16 million to prison costs. As total expenditure on supervised bail over the same period is around £2.4 million, this results in a net benefit of between £2 million and £13 million.

Sensitivity Analysis

8.12 Given the costs and benefits calculated above are estimates based on certain assumptions, it is useful to examine to what extent the variables would have to vary to result in there no longer being a net-benefit (i.e. the cost of bail supervision being equal to the savings from reduced prison numbers). Table 5 shows the results of this exercise for two main variables and across both types of analysis, assuming all else remains equal in each case.

Table 5 - Sensitivity Analysis

  Upper limit : Average SB case length Lower limit: Average Remand length (excluding terminated)
Variable Hypothetical Value Resulting in Costs=Benefits Estimated Value at Present Difference Needed Hypothetical Value Resulting in Costs=Benefits Estimated Value at Present Difference Needed
Average Expenditure Per Case £12,667 £1,412 £11,255
£3,167 £1,412 £1,755
Number of Remand Places Saved 18.5 156.5 138
18.5 41.4 22.9

8.13 We can see that for both variables there would have to be substantial shifts in their values to alter the fundamental outcome that supervised bail results in net-benefits, so long as all assumptions hold.


8.14 Net benefits of supervised bail over the last 3 years are likely to lie somewhere in the range of £2 million to £13 million, with a benefit to cost ratio of between 1.7 and 6.6.

8.15 Based on our assumptions, the average cost of a supervised bail case would have to rise by between 75% and 560% for supervised bail to no longer be cost effective.


Email: Carole Wilson