TOO many of those going through Scotland's courts are ending up stuck in a revolving door of crime and punishment.

The reconviction rate of those serving shorter sentences is unacceptably high.

Two years ago, as a result of an agreement between the SNP and Liberal Democrats at Holyrood the previous year, a presumption against sentences of three months or less was introduced. The Herald supported this move. However, one of the unintended consequences was a rise in the number of sentences of more than three months being handed down by the courts. This appeared to reflect a lack of faith in the administration and security of community-based disposals by sheriffs and judges.

Now the Scottish Government is about to begin a consultation on fitting satellite-controlled trackers on offenders serving non-custodial sentences. In Sweden electronic tagging is said to have halved the reoffending rate compared with those serving similar sentences behind bars. Effectively, this replaces prison with house arrest, though some offenders would also be able to continue working.

Because the offender can be monitored and curfews imposed, tagging can play an important role in disrupting patterns of criminal behaviour, such as nocturnal burglaries, shoplifting or late-night public order offences. The system also can be used to monitor exclusion zones, for example around the home of a victim.

The main potential benefits of such a system are the optimal use of prison space and major cost savings. Tagging costs around a tenth of the expense of keeping a prisoner locked up. Traditionally, though a large proportion of those serving shorter sentences have addiction problems and mental health issues, there is not enough time to tackle them. Arguably, some of the savings from the use of tags could be re-invested in addressing these issues as well as in extending the range of community sentences and making them more robust. Until those dispensing justice have more faith in the efficacy and security of community disposals, their use will continue to be something of a postcode lottery.

Schemes like these also require community support, which is why their success depends on the quality of administration and monitoring. Stories about offenders removing their tags and going on holiday (or a crime spree) would undermine the public's faith in tagging and result in demands to turn the clock back. It is also important to properly evaluate the effectiveness of tagging in bringing down reoffending.

Sentences need to both restrict the freedom of the offender, deter him or her from offending again and protect the safety of the public. Electronic tagging as an alternative to incarceration needs to prove itself against all three tests.

Politicians have been talking about reducing prisoner numbers for decades and yet, despite record-low rates of reported crime, Scotland's prison population reached an all-time high last summer. Satellite tracking of offenders can play a part in reducing those numbers but only if it is properly administered and combined with effective supervision in the community.