Once you have received the SOP(s) from your jurisdiction(s)’ lab(s), the following questions can help you to fill in information above and give you a fuller understanding of a range of issues guiding how the lab conducts its business and the degree to which its protocols are made publicly available:

– Does the lab make its SOPs public?

– If you review them, does the lab include standards for how its analysts should testify in court? Does it say what types of conclusions they can reach for different forensic disciplines?

– Does it allow (or require) them to use phrases like “identification” or “source” when reaching conclusions about pattern disciplines like firearms and fingerprinting?

– Does the lab use any blind checks on analysts; does it require any use of blind verification or blind proficiency testing?

– Does the lab have anything in its SOPs explaining what types of quality controls the lab uses?

Let’s look at an example from Virginia’s Department of Forensic Science (DFS). In the example below, you will see how DFS describes both its conclusion and verification processes:

In its Fingerprint manual, on page 7, the SOP explains what conclusions can be reached and how DFS defines an “identification”:

1.3.11 Identification

    1.3.11.1 Conclusion reached when an examiner determines there is sufficient observed data in agreement to conclude that the friction ridge prints originated from the same source.

    1.3.11.2  Reached when the friction ridge prints have corresponding ridge detail and the examiner would not expect to see the same arrangement of details repeated in a print that came from a different source.

    1.3.12  Inconclusive

    1.3.12.1 Conclusion reached when an examiner determines there is insufficient observed data in agreement or disagreement to conclude that the friction ridge prints did or did not originate from the same source.

    1.3.12.2 The insufficient observed data could be due to absent or unreliable corresponding areas of friction ridge detail.

    1.3.12.3 Reached when the observations do not provide a sufficient degree of support for exclusion or identification.

The SOP also provides information on its efforts to assure the quality of its fingerprint analyses. Beginning on page 54, the SOP describes its verification process, including when blind verification is initiated:

8.5 VERIFICATION

Verifications are divided into two categories: Verification and Blind Verification. In a Verification, the results are not blinded to the verifying examiner. In a Blind Verification, the blind verifying examiner does not have access to the source conclusion(s) rendered by the original examiner.

8.5.1 Verification is the independent application of the Analysis, Comparison and Evaluation steps.

• 8.5.1.1 All conclusions shall be verified.
• 8.5.1.2 The verification shall not be conducted by an examiner that has been solicited for consultation regarding source conclusions.
• 8.5.1.3 If possible, the verification will not be conducted by the technical reviewer.
• 8.5.1.4 Mideo will randomly select cases for Blind Verification. The examiner will be notified of the category of Verification after completing the “Case Status” fieldset associated with the Case Folder.

8.5.1.4.1 If the response is “Proceed with verification / review as necessary”, the examiner will proceed with Verification.

8.5.1.4.2 If the response is “Selected for Blind Verification – Contact Supervisor”, the examiner will proceed with the Blind Verification. 

Similarly, in DFS’s SOP for firearms, they explain on pages 30-31 how to interpret results, and they define what is meant by an “identification”:

5.6.2.1 Identification

Criteria: Agreement of a combination of individual characteristics and all discernible class characteristics where the extent of agreement exceeds that which can occur in the comparison of toolmarks made by different tools and is consistent with the agreement demonstrated by toolmarks known to have been produced by the same tool.

Documentation: One or more photomicrographs shall be made of the marks that are used to support the opinion of identification.

Other marks that are examined, but are not used to support the opinion of the identification, should be documented. However, no photographs or detailed descriptions are necessary for the other marks such as chamber marks, extractor marks or ejector marks.

5.6.2.2 Inconclusive

Criteria: (1) Some agreement of individual characteristics and all discernible class characteristics, but insufficient for an identification. (2) Agreement of all discernible class characteristics without agreement or disagreement of individual characteristics due to an absence, insufficiency, or lack of reproducibility. (3) Agreement of all discernible class characteristics and disagreement of individual characteristics, but insufficient for an elimination.

Documentation: When an item will be reported as insufficient for identification or elimination (inconclusive), mechanism marks that are evaluated shall be documented. The reason(s) why the marks are insufficient shall be documented.

The documentation shall contain each toolmark type mark evaluated to reach an inconclusive conclusion. Marks addressed for cartridge/cartridge case/shotshell/shotshell case comparison may include, but are not limited to: firing pin, breechface, extractor, ejector, chamber, ejection port swipe or other mechanism marks.

5.6.2.3 Elimination

Criteria: Significant disagreement of discernible class characteristics and/or individual characteristics.

Documentation: When items having the same discernible class characteristics will be reported as an elimination based on differences in individual characteristics, differences in marks that are present shall be photographed with documentation for the reason why the marks are eliminated.

When items having different class characteristics will be reported as an elimination, marks that are present shall be photographed or described in detail with documentation for the reason why the marks are eliminated.