West Midlands Police: exploratory analysis of sexual convictions
Algorithmic tool to help ascertain the potential effects of a number of factors on the success or failure of RASSO investigations.
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This algorithmic tool helps to ascertain the potential effects of a number of factors (e.g. the number of officers allocated to an investigation) on the success or failure of RASSO (rape and serious sexual offences) investigations. Statistical modelling was undertaken in order to isolate the effects of a large number of different potential factors on investigations.
As this is an explanatory analysis, the outputs were used to highlight some new questions that can inform potential decisions around which additional variables data should be collected on (e.g. why victims withdraw support for an investigation).
A central aim of this analysis was to inform future resource allocation to RASSO investigations. It helped inform how cases can be allocated to investigators by way of examining the effects of the different features (e.g. the number of officers allocated to an investigation) on the likelihood of an investigation resulting in a charge.
This contributes to a static type of decision making, meaning that it informs a decision at one point in time (e.g. which additional variables to collect data on), but it does not inform decision making on a continual basis.
The number of RASSO investigations coming into WMP’s Public Protection Unit (PPU, the department that undertakes RASSO investigations) has increased substantially over the last 5 years and at the same time the successful conclusion rate for such investigations has dropped considerably. The project therefore aims to identify potential avenues to enable a more effective use of resources and thus contribute to a higher successful conclusion rate.
The results of the analysis have been published on the West Midlands Police and Crime Commissioner’s website.
The report is available within the January 2020 meeting’s files.