Class Characteristics (Footwear)
Definition
The manufactured outsole design features shared by all examples of a specific shoe model: tread pattern, size, shape, and logo placement.
- Includes
- Tread pattern, size, shape, logo placement
- Origin
- Manufacturing design shared across all examples of a model
- Contrasts with
- Individual (acquired) characteristics from wear and damage
- Investigative use
- Narrows a print to a shoe make and model
Common questions
Can class characteristics alone identify a specific suspect's shoe?+
No, class characteristics only narrow the field to a shoe make and model shared by every pair manufactured to that design, so identifying one specific shoe requires individual characteristics such as unique wear patterns, cuts, or embedded debris.
Why match class characteristics first before looking for individual marks?+
Confirming the tread pattern, size and design match a candidate shoe model is a fast, reliable filter that rules out most shoes quickly, so examiners only invest time searching for finer individual wear features on the remaining plausible candidates.
Do class characteristics change over a shoe's production run?+
Manufacturers periodically update outsole moulds, so the same shoe line can show slightly different class characteristics across production years, which examiners use to narrow the likely purchase or manufacture window of a matching shoe.
Related terms
- Dental Stone
- A gypsum-based casting material harder and finer than plaster of Paris. Preferred for forensic 3-D casts because it captures detail at the...
- ESLA (Electrostatic Dust-Print Lifter)
- A device that applies a high-voltage static field to a metallised film, attracting dust particles from a footwear impression on a hard...
- Perpendicular Camera Alignment
- The requirement that the camera lens be directly above the impression centre with the sensor plane parallel to the impression plane; prevents...
- R V. Mohan (1994) + White Burgess Langille Inman (2015)
- Canadian Supreme Court framework for forensic-expert admissibility: Mohan sets relevance + necessity + qualification + no exclusionary rule; White Burgess adds an...
- Randomly Acquired Characteristics (RACs)
- Post-manufacture features (cuts, gouges, embedded material, crack patterns) unique to a specific shoe sole or tyre; the highest-level individualising features in impression...
- SICAR (Shoeprint Image Capture and Retrieval)
- FBI and Foster and Freeman (UK) outsole design database used for class-characteristic database searches; referenced in US, UK, Australian, and Canadian forensic...
- Snow-Print Wax
- A spray wax applied in thin coats to snow impressions before casting to provide a thermal barrier, allowing Dental Stone casting without...
- Subclass Characteristics (Footwear)
- Features shared by a subset of shoes from the same mould or production batch; may mimic individual characteristics if not properly distinguished.
- SWGTREAD
- Scientific Working Group for Shoeprint and Tire Tread Evidence; US body that developed the dominant guidelines for footwear and tyre-mark examination, class-subclass-individual...
- Tracking Evidence (TE) Database
- FBI database of tyre tread design patterns, used for class-characteristic identification in tyre-mark cases; accessible to partner agencies internationally.
- Treadmate
- RCMP database of outsole designs for footwear comparison, used by Canadian forensic laboratories and accessible to partner agencies.