2.8 Although a number of measures are common to both PFI and public prisons, target levels differ between the two sectors. In some cases, this difference reflects the areas where the private sector has been required by the contract to perform better than the public sector. For example, the average purposeful activity target for local prisons operating in the public sector is 20.6 hours per prisoner per week. The equivalent figure for PFI and privately-managed local prisons is 29.5 hours. Similarly, the contracts for private prisons stipulate relatively high levels of time-out-of-cell for prisoners compared to the equivalent targets in public prisons. With the exception of Grendon which operates a therapeutic community unique in the publicly-run prisons, all the public prisons we examined had lower time-out-of-cell targets than PFI prisons.