The use of random sampling in investigations involving child abuse material

This paper presents a methodology which has been used to address two ubiquitous problems of practising digital forensics in law enforcement, the ever increasing data volume and staff exposure to disturbing material. It discusses how the New South Wales Police Force, State Electronic Evidence Branch (SEEB) has implemented a “Discovery Process”. Using random sampling of files and applying statistical estimation to the results, the branch has been able to reduce backlogs from three months to 24 h. The process has the added advantage of reducing staff exposure to child abuse material and providing the courts with an easily interpreted report. The software portion of the Discovery process is contained within the framework of Guidance software’s forensic tool, EnCasea. This is then further customised for the Discovery process by using the EnCase EnScripta language. a 2012 S. Pleno, B. Jones & M. Wilkinson. Published by Elsevier Ltd. All rights reserved.

[1]  Y. Jewkes,et al.  Policing the filth: The problems of investigating online child pornography in England and Wales , 2005 .

[2]  D. Sachau,et al.  Secondary Traumatic Stress and Burnout among Law Enforcement Investigators Exposed to Disturbing Media Images , 2010 .

[3]  Mark L. Berenson,et al.  Business Statistics , 2009, International Encyclopedia of Statistical Science.

[4]  Chukiat Viwatwongkasem,et al.  Revisiting proportion estimators , 2005, Statistical methods in medical research.

[5]  Jeff Sauro,et al.  Estimating Completion Rates from Small Samples Using Binomial Confidence Intervals: Comparisons and Recommendations , 2005 .

[6]  Daniel.  Business Statistics , 1991 .

[7]  M. Krause.  Identifying and Managing Stress in Child Pornography and Child Exploitation Investigators , 2009 .

[8]  Jim Fraser,et al.  Forensic Science: A Very Short Introduction , 2010 .

[9]  Barry Levine,et al.  Principles of Forensic Toxicology , 1999 .

[10]  Richard D. De Veaux,et al.  Intro Stats , 2002 .

[11]  J. Vaizey.  Introduction to Sociology , 1970, Nature.

[12]  H Cockburn.  Director of Public Prosecutions V Shaw , 2013 .

[13]  Informatika.  Child Exploitation Tracking System , 2010 .

[14]  Bruce Budowle,et al.  Quality Sample Collection, Handling, and Preservation for an Effective Microbial Forensics Program , 2006, Applied and Environmental Microbiology.

[15]  T. Holt,et al.  Examining Job Stress and Satisfaction Among Digital Forensic Examiners , 2011 .

[16]  Leevan Ling,et al.  Confidence intervals for a difference between proportions based on paired data , 2010, Statistics in medicine.

[17]  L. Brown,et al.  Interval Estimation for a Binomial Proportion , 2001 .

[18]  Ken Browne.  An Introduction to Sociology , 1992 .

[19]  Taro Yamane.  Statistics: An Introductory Analysis , 1965 .

[20]  J. Rouleau,et al.  Multiple paraphilic diagnoses among sex offenders. , 1988, The Bulletin of the American Academy of Psychiatry and the Law.

[21]  A. Agresti,et al.  Approximate is Better than “Exact” for Interval Estimation of Binomial Proportions , 1998 .