How reliable is Imagery Analysis?
Two people or objects can share similar characteristics, and it is recognised that two people may be difficult to tell apart, even if standing side-by-side, let alone in poor quality CCTV. This means that positive identification (i.e. image X is of Person Y) is generally not possible.
However, FVS can compare available imagery with the candidate for differences that would positively eliminate them. It is generally accepted that finding ‘no differences’ is supportive evidence that the subject in the footage being analysed and the candidate is one and the same, and they cannot be eliminated as a candidate.
No scales or statistical databases exist that can precisely evaluate findings and conclusions, so FVS use a standardised scale as a method of providing a subjective expert opinion:
- Lends no support*
- Lends limited support
- Lends moderate support
- Lends support
- Lends strong support
- Lends powerful support
*(Extract taken from the Forensic Imagery Analysis Group (FIAG) guidelines, a sub-group of the British Association of Human Identification (BAHid) and the Chartered Society of Forensic Sciences).