Average length of stay for prisoners between 2015 & 2020: FOI release

Information requested

In the Scottish Government’s publication of annual prison population statistics, it details the number of prisoners who were liberated from prison that had at least a 4 year stay in prison. What was the average length of stay in prison for such individuals? Please provide this information, denoted in years (and months if possible), for the years of 2015-16, 2016-17, 2017-18, 2018-19 and 2019-20. For the avoidance of doubt in what I’m referring to, in 2019-20 there were 199 prisoners who left prison after serving at least 4 years in prison.

Response

Please find below the average length of time spent in custody by individuals leaving prison after 4 years or more in financial years 2015-16 through 2019-20.
 

Financial Year	Departures after 4 or more years	Median Length of Custody (years)
2015-16	218	5.0
2016-17	228	5.5
2017-18	184	5.4
2018-19	233	5.4
2019-20	199	5.3

Note that the median time in years has been provided for each financial year. This metric has been chosen in place of the mean as a better measure of central tendency in this time-bounded dataset. Durations are constrained at the lower end of the scale by the 4 year minimum, and at the upper end by the data held in the prisoner records system (PR2), which was brought online in 2003. A mean would be influenced by the construction of the data, with a greater range of possible values for later years. The median is not affected by this artificial bounding.

About FOI

The Scottish Government is committed to publishing all information released in response to Freedom of Information requests. View all FOI responses at http://www.gov.scot/foi-responses.