Request New Error Types for the NumisDex Catalog

Help Us Expand the Error Type Taxonomy

NumisDex currently recognizes 63 standardized error types across 8 categories — from Doubled Dies and Die Breaks to Planchet Errors and Strike Errors. This taxonomy is the backbone of how we classify and catalog coin varieties, and it powers the filters, search facets, and ND codes throughout the platform.

But numismatics is a living field. New varieties are discovered, classification standards evolve, and the community's understanding deepens over time. That's why we've built a system for you to propose new error types directly.

How to Request a New Error Type

There are two ways to submit a request:

From the submission form — When you're submitting a new variety and can't find the right error type, click the "Can't find your error type? Request one" link in the Error Classification section. This opens the request form right where you need it.
From the dedicated page — Visit /catalog/request-error-type to submit a request anytime, even if you're not in the middle of a submission.

What Makes a Good Request

When proposing a new error type, a strong request includes:

A clear, descriptive name — Follow the naming conventions of existing types. For example, "Doubled Die Obverse" rather than just "DDO" or "doubled die".
A suggested category — Where does this fit? Doubled Die Family, Die Damage Family, Strike Errors, etc. If it doesn't fit existing categories, say so.
A detailed justification (minimum 50 characters) — Explain why this error type is distinct from existing ones. What are its defining characteristics? How prevalent is it? Why does it deserve its own classification?
Example listings — If you can link to 1-3 existing NumisDex listings that demonstrate this error type, it helps the admin team understand exactly what you're describing.

What Happens After You Submit

Your request goes into an admin review queue. The admin team will:

Approve — Your proposed error type is added to the catalog. It immediately appears in submission forms, filters, and search facets. You'll receive a notification confirming the addition.
Merge — If your proposal maps to an existing error type (perhaps under a different name), the admin will link it and explain the connection. You'll be notified with details.
Deny — If the request doesn't meet the criteria, you'll receive a notification with the reason. This might happen if the error type is too niche, overlaps with existing types, or needs more evidence.

In all cases, you'll receive a platform notification with the outcome.

Current Error Type Categories

For reference, here are the 8 categories currently in the taxonomy:

Doubled Die Family (6 types) — DDO, DDR, doubled working hubs, master die doubling
Die Damage Family (17 types) — Cuds, die breaks, die cracks, BIE cents, die chips, and more
Die Clash Family (8 types) — Standard clashes, counter clashes, floating clashes, radical MAD clashes
Hub/Punch Errors (9 types) — RPMs, RPDs, overdates, misplaced dates, over mint marks
Planchet Errors (6 types) — Clipped planchets, laminations, wrong planchets, missing cladding
Strike Errors (9 types) — Off-center, broadstrikes, multi-strikes, rotated dies, strike-throughs
Collar Errors (2 types) — Collar breaks and collar clashes
Other (6 types) — Trail dies, transitional designs, VAM varieties, UFOs, counterfeits

Browse the full taxonomy in the Learn section or see it in action on the catalog search page filters.

Discussion

Have thoughts on error types that should be added? Think a category needs to be split or reorganized? Reply to this thread to discuss with the community. Your input helps shape the taxonomy that everyone uses.

If you have a specific proposal ready, head to the request form to submit it formally.