A standard operating procedure for document examination
Standard operating procedures
A standard operating procedure best suited for their needs is developed by each document examiner. Regulated industries dictate the standards to be followed. For non-regulated industries, the examiner can follow ASTM/SWGDOC/SAFE or some other industry-recognized standards.
When the document examiner’s standard operating procedure (SOP) is based on the ASTM, SWGDOC, SAFE, or other industry recognized standards, and the document examiner follows the SOP, the document examiner is using a generally-accepted practice.
Unlike regulated industries that dictate the standards to be followed, non-regulated industries are not audited to ensure compliance to standards. Forensic document examination is a non-regulated industry.
When audits are performed in regulated industries such as banking or food processing, the auditor examines whether the company is following the stated internal procedures. The internal procedures are audited to determine whether they align with the regulations and standards for the industry.
When a document examiner’s standard operating procedures (SOP’s) are based on the ASTM/SWGDOC/SAFE standards, the document examiner is using a generally-accepted practice.
The SOP typically describes what the document examiner does when contacted for a new case, how the documents are handled when received, how they are stored and protected, etc. The SOP also describes the standard procedure used to examine documents. It may describe what the examiner looks for during an examination.
The SOP is descriptive rather than prescriptive. The reason is each case is different. Often the examiner must adapt the SOP to the specific case. As an example, the SOP may require the examiner to obtain a minimum of 15 exemplars of the person whose signature is being examined. This sample may prove insufficient for the examiner to reach an opinion other than inconclusive. Here the examiner will request additional exemplars to strengthen the opinion in one direction or the other. In another case the examiner may not be able to obtain 15 exemplars. Upon examination, the examiner may reach an opinion on the authenticity of a signature.
I had a case in which my opinion was a person probably did not sign the document. Additional exemplars were provided. One of the exemplars showed the attribute of the questioned signature that is not in other exemplars. This discovery caused my opinion to change to inconclusive.
Example of a portion of a Standard Operating Procedure
Step 1: Sort the documents in chronological order
Step 2: Each document is given a unique identifier. The identifier for known documents begins with the letter K followed by a numerical, sequential identifier such as K001. The identifier for the questioned documents begins with the letter Q followed by a numerical, sequential identifier such as Q001.
Step 3: Create a file folder on the computer and in the hardcopy files for the case.
Step 3 takes one of two forms:
- When I receive hard copy (paper) documents I place a sticky note on the paper document, labeling it with the assigned numerical identifier. This enables easy identification of the printed copy of the image. I scan them into the computer with a flatbed scannerusing at least 800 pixels per inch (PPI). I store the documents in a tagged information file format (TIFF), which has no loss of resolution due to file data compression. Some document examiners use JPG file format. JPG compresses the data in the file, resulting in loss of resolution. The TIFF is a huge file. A color 8.5” x 11” scanned page at 800 PPI is sometimes more than 175 megabytes in size.
- Sometimes I receive documents in electronic form such as PDFor JPEG. Images of bank checks typically are scanned images from the bank. I ask the client to send the PDF file, rather than printing the file and sending the printed page to me. The PDF has more detail than the printed image. Sometimes, a client has only an electronic image of a document.
- I read the PDFor JPEG files into Photoshop, and then save them as TIFF and Photoshop PSD files with the proper nomenclature. When the PDF file contains several pages, I extract the pages I will use from the file, saving each with the name that identifies the purpose and source. I use Photoshop to annotate the name of the file, such as K004, onto the image. An example of a file name is K004 Jones Trust page 4.
- I rename all other forms of electronic documents with the proper nomenclature and save them into the case folder.
Step 4: Each document is examined for clarity. If the document has not been scanned at a quality that is usable, the document is noted as not usable. If the questioned document(s) are not usable, the analysis cannot be performed.
Step 5: Use Photoshop to extract the writing to be examined from the pages. This procedure removes the background noise such as printed text and other writing. Only the writing to being examined, such as a signature and the signature line (if any), remains. Background noise can bias the view of the writing causing the examiner’s brain to see patterns that do not exist, or miss important aspects of the writing.
Step 6: For signatures, combine the known writing on as many single pages as required to hold them. This permits examination of the writing for common traits and differences. I then extract the questioned signature from the questioned documents and place it on the page with the known writing. I often change the color of the questioned writing to easily distinguish between the known and questioned signatures.
Step 7: Begin to make the comparisons. Make a copy of the questioned signature to produce an overlay for comparing with the known writing. Change the color of the copy to red.
Step 8: Place the copy of the questioned writing over the known writing to compare the two for similarities and differences.
Step 9: For each known signature, proportionally set the questioned writing to a height that matches the known writing. This doesn’t change the proportions of the writing. Due to variations, research shows that capital letters are not useful for height comparison.
Step 10: When necessary, measure the letters in the writing using the Photoshop ruler tool. Both heights and angles are measured. Export the data to Microsoft Excel for statistical analysis. Statistical analysis software is also used.
When I discover common features in the known writing, I enlarge those features to learn the details of the way the writing strokes were formed. Features such as connections between letters, initial and terminal strokes, and unique idiosyncrasies are examined. I measure relative sizes to determine whether there is consistency in the intra-writer variability.
Essentially, my examination starts at a gross level then works to a more detailed analysis. The gross-level examination is used to determine whether a more detailed analysis is necessary.
The document examiner’s SOP includes asking questions of the client to determine the source of the questioned document and exemplars. As an example, the document examiner may need to learn whether the suspected writer of the questioned document had access to the writing instrument used to execute the document.
Summary for using a standard operation procedure
Many times, in trial and deposition I’ve been asked whether I use industry standards for performing the examination. I always state that I use the SWGDOC, SAFE, and/or ASTM standards as appropriate. These standards do not offer a standard operating procedure. They offer guidance on steps for examining a document. A standard operating procedure offers the detail of the applied methodology. When a document examiner follows a standard operating procedure, there is a greater chance that steps will not be missed in the analysis.
Some document examiners state they have a methodology because they use ACE-V (Analysis, Comparison, Examination, and Verification). ACE-V is not a methodology. The methodology is the standard operating procedure that would be used to implement the process.
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