Prison population projections: November 2023 edition

This report presents short-term Scottish prison population projections for the six month period from October 2023 to March 2024. They have been produced using ‘microsimulation’ scenario modelling which simulates prison arrivals and departures, and estimates the number of individuals in prison.

6 Conclusions

The modelling indicates a projected range of between 7,500 and 8,650 for the average daily total prison population in March 2024. As at 1st October 2023, the prison population was around 7,950.

Further scenarios have been added to the prison projections. In the previous publication only low, central and high court throughput scenarios were reported. For this update, in addition to these three court throughput scenarios, there are six new scenarios featuring varying remand arrivals (low, central and high) combined with court throughput variations (also low, central and high). Over the course of the next few months remand arrivals, sentenced arrivals and case conclusion levels will be monitored to assess with which scenarios the actual prison population numbers are most closely aligned.

For several reasons, modelling the future prison population using the microsimulation gets less accurate the further ahead it is projected (whether due to systematic errors in the model, inaccurate assumptions due to unforeseen circumstances, or due to changed circumstances that the model is not built to account for). Experience to date suggests that to ensure reliable projections, a maximum duration for the projection of six months is preferred.

As previously highlighted, the key factors impacting changes in the prison population in the short term will be the flows into and out of the remand and sentenced populations. This is influenced by the court recovery programme, for example the resource re-allocation from summary to solemn which took place in April 2023. SCTS reporting has indicated that recent elevated levels of summary demand has meant that the level of outstanding summary trials has stabilised rather than continuing to fall. This has led to a review of options to address this challenge if the current level of demand for summary trials continues in the near term[23].



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