text: **Prison Population Projections 2014 – 2020**
  
  The approach for the other sub-populations is similar and has not been 
  substantially revised since the 2013 publication. The methodology applied to 
  each is briefly outlined below. 
  
  The recall population is projected going forward based on time-series data 
  available to October 2014. 
  
  For remand prisoners the average time served on remand is calculated from 
  the ratio of the remand population to remand receptions. The modelled stock 
  of prisoners is calibrated to historical actuals by varying levels of receptions. 
  The remand population is generated in two parts both using this approach – 
  untried remand and unsentenced remand populations being treated 
  separately. 
  
  IPP and life sentence prisoners have an extra section in the stock-flow 
  structure which models the indeterminate nature of their sentence lengths. 
  Outflows for IPP and life sentence prisoners depend on the tariff lengths they 
  receive and on the frequency and outcome of Parole Board hearings. The 
  values of these parameters are set and calibrated to reflect the most recent 
  data on Parole Board outcomes. 
  
  NOMS have made an agreement with the Home Office to hold an increased 
  number of immigration detainees, which are only seen in the final two periods 
  of historical data. The projected size of the non-criminal population is therefore 
  set equal to the average size of the non-criminal population over the last two 
  months of available data. This ensures that the non-criminal projections reflect 
  the latest and most accurate count of the non-criminal population. 