The challenges of identifying and classifying child sexual abuse material

Juliane Kloess, Jessica Woodhams, Helen Whittle, Tim Grant, Catherine Hamilton-Giachritsis

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The aim of the present study was to (a) assess the reliability with which indecent images of children (IIOC) are classified as being of an indecent versus nonindecent nature, and (b) examine in detail the decision-making process engaged in by law enforcement personnel who undertake the difficult task of identifying and classifying IIOC as per the current legislative offense categories. One experienced researcher and four employees from a police force in the United Kingdom coded an extensive amount of IIOC (n = 1,212-2,233) to determine if they (a) were deemed to be of an indecent nature, and (b) depicted a child. Interrater reliability analyses revealed both considerable agreement and disagreement across coders, which were followed up with two focus groups involving the four employees. The first entailed a general discussion of the aspects that made such material more or less difficult to identify; the second focused around images where there had been either agreement (n = 20) or disagreement (n = 36) across coders that the images were of an indecent nature. Using thematic analysis, a number of factors apparent within IIOC were revealed to make the determination of youthfulness and indecency significantly more challenging for coders, with most relating to the developmental stage of the victim and the ambiguity of the context of an image. Findings are discussed in light of their implications for the identification of victims of ongoing sexual exploitation/abuse, the assessment and treatment of individuals in possession of IIOC, as well as the practice of policing and sentencing this type of offending behavior.
Original languageEnglish
Pages (from-to)173-196
Number of pages24
JournalSexual Abuse: A Journal of Research and Treatment
Issue number2
Early online date1 Sept 2017
Publication statusPublished - 1 Mar 2019

Bibliographical note

Funding: The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research was supported in part by grants from the ESRC IAA Fund (Birmingham), EPSRC IAA Fund (Bath), EPSRC KTS Scheme (Birmingham), as well as the College of Policing, Home Office and HEFCE.


  • indecent images of children (IIOC)
  • child sexual abuse material
  • child pornography
  • Internet sexual offenses
  • online child sexual abuse


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