If the Shoe Fits: A randomised control trial measuring the effectiveness of digitised in-custody footwear technology compared with paper based methods

Randomised Control Trial Status


Geographical area

​London Borough of Barnet; North London; Metropolitan Police Service.

Research Institution / Organisation

University of Cambridge

Contact Name

Julie Henderson

Project Start Date

May 2017

Participants - inclusion criteria

​All persons arrested for a recordable crime.

Target Sample Size

​128 samples.

Study Design

​The study involves a randomised controlled field trial, with allocation of footwear samples into a digitised in-custody footwear technology or the business-as-usual, paper-based model. Randomisation is carried out using the Cambridge Randomiser 2.0.


​Automated randomised allocation.

Summary of Findings

​This RCT provides evidence which supports the hypotheses:

  1. the average speed of obtaining a Tread Finder Sample and a paper-based sample are similar – approximately 4 minutes – however the Tread Finder arm provided pattern matching and coding within the capture process, whereas the paper based method does not; 
  2. the average time to obtain an automated intelligence package using the treatment is 08:40 minutes, while nil packages were detected using the comparison system. Evidentiary materials from Tread Finder are linked to 16 intelligence links out 64 samples, with nil returns in the paper-based arm of the experiment.

Date last updated

Tuesday 26 June 2018
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