A justice thinktank is scratching its head over the reasons behind a significant decline in the number of community sentences in England and Wales.

In a research report, Community sentences across borders, the Centre for Justice Innovation says there has been a 24% decrease over the past decade. However, the number of short-term prison sentences has also declined. By contrast, in Scotland, community sentences have risen by 18% over the past 10 years, which would explain the 23% decline in short-term prison sentences.

The thinktank, which has long championed problem-solving courts, says its analysis shows that the relationship between community sentences and short prison sentences is complex. 'It is certainly not a straightforward relationship, where if the use of community sentences goes up, short prison sentences always go down or vice versa.

'In England and Wales, the sharp decline in the use of community sentences has not led to an increase in short prison sentences - in fact they too have gone down. That only further confirms research from elsewhere that the relationship between community sentences and the use of prison is sensitive to all manner of factors.'

The thinktank 'tentatively suggests' that community payback orders and the presumption against short prison sentences in Scotland explain the rise in community sentencing.

In Scotland, the community payback order was introduced in 2011 and replaced several community disposals including probation orders and community service orders. The Criminal Justice and Licensing (Scotland) Act 2010 introduced a presumption against sentences of less than three months. The act requires the court to pass a sentence of less than three months only if no other appropriate disposal is available, and to record its reasons. 

A Scottish government report on re-conviction rates shows that re-offending for all offenders was at an 18-year low.

The centre acknowledges that its report 'only begins to understand' why England and Wales, and Scotland, are on different journeys in the use of community sentencing. However, with evidence suggesting that community sentences are more effective and better value for money than short prison sentences, the thinktank suggests policy-makers look across the border.