NYCLAC Report Standardization Project
Trace Evidence
Open All Categories | Close All Categories
Standardized Report Components
- Unique case identifier on each page of report (such as lab number)
- Title of the report (such as “report of laboratory analysis”)
- Identification of the laboratory
- Submitting Agency Info or at a minimum submitting agency
- List or explanation of items examined
- General indication of methodology utilized
- Results/conclusions
- Date report issued
- Signature and title of examiner (or electronic equivalent)
- Pagination of the report (example page 1 of 2 etc.)
- Statement regarding the report does not constitute the entire case file or equivalent
- Statement that definitions of terms used in the report can be located at the DCJS website and if applicable on the laboratory website or attached to report
Additional Discipline Specific Report Components:
- Sample selection, if it occurs, clearly reflected in the report
Standardized Language/Statements
The following consists of report writing examples representing typical results and report wording used in trace evidence examinations. Due to the range of materials and the varied condition and quality of evidence samples encountered, modifications to the following report wording should be utilized to more clearly convey results and conclusions of examinations.
Basis for conclusions will be included in the report.
When associations are made, the significance of the association shall be communicated clearly and qualified properly in the report (ISO/IEC 17025:2005 5.10.3.5).
Class Comparisons
Positive
Results
- The questioned sample (Q) and known sample (K) are consistent... and/or
- No discriminating differences were observed between the questioned sample (Q) and known sample (K).
- Include the actual techniques used in comparison and the properties examined.
Conclusions
The questioned sample could have originated from … as represented by the known submitted exemplar or from another source exhibiting all of the same analyzed/measured characteristics.
Negative
Results
State that the items compared were different and state properties.
Conclusions
- Do not share a common origin/source (when you do not have a known)
- Could not have originated from the source represented by K (when you have a known)
Inconclusive
State/explain the limiting factors of the exam:
- No conclusion could be reached due to (state/explain limiting factors).
Disclaimers and Qualifying Statements (where applicable)
Include limiting factors, such as size, and state that they preclude further testing which can provide additional information.
Impressions / Imprints Positive
Results
State what class characteristics are the same (or different) between the questioned and known and whether or not there are any corresponding individual characteristics.
Conclusions
- Identification:Q was made by K.
- Inclusion: Q could have been made by K or another item exhibiting the same characteristics.
Elimination
- State/explain differences observed.
- Q could not have been made by K.
Inconclusive
State/explain what the limiting factors of the exam are, such as if there is insufficient detail or if the pattern area is too small:
- No conclusion could be reached due to…
Disclaimers and qualifying statements Impressions / Imprints
- Qualify basis for results. Listing the characteristics is sometimes desirable (i.e., the same design, spacing) it can then be stated why a stronger conclusion was not made.
- No distinguishable difference in tread pattern, however, the lack of (state limiting factors i.e.: lack of individual characteristics observed) precludes a stronger association.
- X corresponding individual characteristics (or other features) increase the value of the comparison
Physical Match / Physical Fit Examination
Positive
Results
Describe the condition(s) of the edge(s) and state that they were examined and compared for physical match/fit.
Conclusions
Q and K were at one time joined together…
Elimination
- Q and K were not previously joined together… as represented by…
- If no physical match was established, state such and refer to class comparison (if applicable).
Inconclusive
Due to (state reason), it cannot be concluded whether Q and K were at one time joined together.
Disclaimers and qualifying statements
N/A
Hair Comparisons
Positive
Results
Known and questioned hairs exhibit similar visual and microscopic characteristics. The questioned hair appears/may be suitable/unsuitable for nuclear DNA and/or mitochondrial DNA analysis.
Conclusions
The Q could have originated from the K as represented by the submitted (analyzed) exemplar/reference hairs or from another individual/source whose hairs exhibit the same physical/microscopic characteristics.
Negative
Results
Known and questioned hairs exhibit dissimilar visual and microscopic characteristics/dissimilar physical characteristics/significant microscopic differences. The questioned hair appears/may be suitable/unsuitable for nuclear DNA and/or mitochondrial DNA analysis.
Conclusions
- The Q is not consistent with originating from the K as represented by the submitted (analyzed) exemplar/reference hairs - OR-
- The Q could not have originated from the K as represented by the submitted (analyzed) exemplar/reference hairs.
Inconclusive
Clearly communicate reasons a definitive conclusion could not be reached.
For example(but not limited to):
- Comparison of the questioned hair to the known standards revealed differences or comparison of the questioned hair to the known standards revealed similarities but the questioned hair lacks enough features for comparison and/or the known sample is insufficient.
- The questioned hair is not identifiable or is not suitable for reliable comparisons…… therefore no conclusion can be reached.
- No conclusion could be reached as to whether or not Q could have originated from a source as represented by K.
- The questioned hair appears/ may be suitable/ unsuitable for nuclear DNA and/or mitochondrial DNA analysis.
Disclaimers and qualifying statements
It should be noted that microscopic hair comparisons are not a means of absolute personal identification or individualization. DNA could give a more conclusive result than microscopic comparison alone.
Optional Statement (if no references are submitted): Additional information could be provided by a combination of microscopic comparison followed by DNA analysis.
The following qualifying statement will be added when racial characterizations are made based on microscopic hair examinations: It should be noted that racial classifications of hairs are based on microscopic characteristics which are typically observed in hairs from individuals of a given racial group, and these classifications may or may not correspond to an individual’s racial origin or self-identification.
Chemical Identification / Explosives Identification
Identification:
Positive
Results
State what tests you used and what you identified.
Conclusions
- Identity of material was identified. This is commonly found in (but not limited to).
- Example for bank dye packs: MAAQ was identified by instrumental analysis (GC/MS). This chemical is a component of dye packs.
Indication:
Positive
Results
State tests used and chemicals indicated. Clarify not confirmed/identified.
Conclusions
- Substance was indicated based on…Include why an identification can’t be made (where applicable).
- Example: Sample size was insufficient for instrumental analysis necessary for positive identification.
Negative
State tests conducted.
Conclusions
Requested substance was not identified.
Inconclusive Chemical Identification / Explosives Identification
State tests conducted, and reasons as to why inconclusive.
- No conclusion could be reached due to
(General Physical Comparisons) Motor Vehicle Lamp Examination
Positive
Results
- Describe condition of bulb and filament.
- Item exhibits characteristics (list) consistent with (hot shock, hot break)…
Conclusions
… indicating that the filament was “on” at time of damage.
Negative
Results
- Describe condition of bulb and filament.
- Item exhibits characteristics (list) consistent with (cold shock, cold break)…
Conclusions
… indicating that the filament was “off” at time of damage.
Inconclusive
Results
Describe condition of bulb and filament.
- Item appears normal…
Conclusions
… indeterminate, no determination whether the filament was “on” or “off” at time of damage.
Disclaimers and qualifying statements
For hot shock: It is not possible to determine if filament was damaged at time of collision.
Other Disclaimers and Qualifying Statements
Because mass produced items (case dependent, i.e., textile fibers, plastic bags, and plastic gloves) are mass produced, it is not possible to state that a fiber originated from a particular textile source to the exclusion of all other materials composed of fibers which exhibit the same (applicable, i.e., chemical and optical) properties.
For blue denim and white cotton fibers:
If no further analysis was warranted: These fibers are ubiquitous and have limited forensic value and therefore no further analysis was performed
For plastic bags (where applicable):
It was concluded that the bags were made consecutively, therefore it is possible, but cannot be conclusively determined that the bags came from the same physical package. This statement may be part of class comparison results for plastic bags.
For glass:
Elemental analysis (which is not available at this laboratory) could provide additional discrimination.
Database Inquiry
- State database used, such as PDQ, Tread Design Guides.
- State limitations (i.e.:List is not all-inclusive, do not limit search to items on list…)
- Specify that information is for investigatory purposes only.
- If further analysis is required, state that samples for comparison purposes would have to be submitted.
Standardized Terms & Definitions
Class
A group, set or kind marked by common attributes or a common attribute. (ASTM E1732-12)
Class Characteristics
The attributes that establish membership in a class. (ASTM E1732-12)
Consistent
No significant differences are discernable between two objects with respect to class characteristics (size, shape, dimensions, and physical properties and composition). Items share sufficient similarity in observed characteristics such that they could not be distinguished from sharing a common source. Due to the mass manufacturing process, items with indistinguishable class characteristics cannot be positively identified as sharing common origin without the addition of sufficient identifying characteristics.
Disclaimer
Limitation of the examination/technique/science.
Discriminating Difference
A feature that serves to exclude two items from sharing a common source.
Identification
- Physical Comparison
A positive association of a questioned to a known item to the exclusion of all others. - Chemical Analysis
Analysis conducted confirms presence of a material.
Indication
The analysis conducted suggests a material/condition is present, but is not sufficient for identification / a definitive conclusion.
Individual Characteristic
A randomly acquired characteristic that contributes to the uniqueness of an item.
Physical Match
Re-alignment of segments based on randomly occurring features to show that they were once one item
Qualifying Statement
Refers to analysis / comparison in case. May strengthen or weaken the association.