Significance and Use
3.1 Digital and multimedia evidence forensics is a complex field that is heavily reliant on algorithms that are embedded in automated tools and used to process evidence. Weaknesses or errors in these algorithms, tools, and processes can potentially lead to incorrect findings. Indeed, errors have occurred in a variety of contexts, demonstrating the need for more scientific rigor in digital and multimedia evidence forensics. This guide proposes a disciplined approach to mitigating potential errors in evidence processing to reduce the risk of inaccuracies, oversights, or misinterpretations in digital and multimedia evidence forensics. This approach provides a scientific basis for confidence in digital and multimedia evidence forensic results.
3.2 Error rates are used across the sciences to characterize the likelihood that a given result is correct. The goal is to explain to the reader (or receiver of the result) the confidence the provider of the result has that it is correct. Many forensic disciplines use error rates as a part of how they communicate their results. Similarly, digital and multimedia evidence forensics needs to communicate how and why there is confidence in the results. Because of intrinsic difference between the biological and chemical sciences and computer science, it is necessary to go beyond error rates. One difference between chemistry and computer science is that digital technology is constantly changing and individuals put their computers to unique uses, making it infeasible to develop a representative sample to use for error rate calculations. Furthermore, a digital and multimedia evidence forensic method may work well in one environment but fail completely in a different environment.
3.3 This guide provides a disciplined and structured approach for addressing and explaining potential errors and error rates associated with the use of digital and multimedia evidence forensic tools/processes in any given environment. This approach to establishing confidence in digital and multimedia evidence forensic results addresses Daubert considerations.
Scope
1.1 This guide provides a process for recognizing and describing both errors and limitations associated with tools, techniques, and methods used to support digital and multimedia evidence forensics. This is accomplished by explaining how the concepts of errors and error rates should be addressed in digital and multimedia evidence forensics. It is important for practitioners and stakeholders to understand that digital and multimedia evidence forensic techniques and tools have known limitations, but those limitations have differences from errors and error rates in other forensic disciplines. This guide proposes that confidence in digital and multimedia evidence forensic results is best achieved by using an error mitigation analysis approach that focuses on recognizing potential sources of error and then applying techniques used to mitigate them, including trained and competent personnel using tested and validated methods and practices. Sources of error not directly related to tool usage are beyond the scope of this guide.
1.2 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
