What is attachment validation?
Attachment validation is the check that a required supporting document has arrived in a usable state. It confirms the file is present and legible before testing whether it is the type the rule names. A certificate uploaded as a photograph of a screen satisfies none of these while appearing to satisfy all of them.
Why a present attachment is rarely a valid one
The commonest finding at the close of a regulated intake cycle is a folder of attachments nobody could read. A certificate photographed at an angle, a password-protected file the applicant forgot to mention: each passed the upload step and failed assessment weeks later. Upload confirmation is the moment an applicant believes the task is finished, so every check deferred past it becomes a letter and a delay.
- An upload that succeeded technically can still be unreadable to an assessor.
- Expiry dates on certificates are the most frequent cause of late rejection.
- The applicant has the document to hand at upload and not six weeks later.
- Checking the type at entry prevents a whole class of avoidable correspondence.
How attachment validation works
- The rule declares which document types satisfy each requirement before any upload occurs.
- Format and file integrity are verified the moment the file arrives.
- Legibility is assessed on the rendered page rather than on the file header.
- The document is classified to confirm it matches the requirement it was attached to.
- Dates and identifiers are extracted and checked against the requirement's own conditions.
- Any failure returns a specific reason while the applicant is still on the page.
How attachment validation is evaluated
Attachment validation is judged on how many documents reach an assessor in usable condition. Measure the following across uploads already received:
- share of uploads rejected at entry rather than at assessment
- proportion of attachments an assessor judges legible
- accuracy of document type identification against assessor confirmation
- rate of expired documents accepted into assessment
- median attempts an applicant needs per attachment
Limitations, risks and common failure modes
- Scanned photographs pass every technical check and defeat extraction entirely.
- File type restrictions push applicants into converting documents badly.
- Expiry is verified against the upload date rather than the decision date.
- A rule accepts any document of the right type without checking whose name it carries.