Rummy How-To: Build a Simple Error Taxonomy

“I made a mistake” is true but not very useful. An error taxonomy gives each problem a category and a next action. You do not need a large spreadsheet; four or five labels are enough to turn a vague review into a practical adjustment.

Start with reading errors. These include misidentifying a rank or suit, overlooking a visible discard, or misunderstanding which cards were selected. The remedy is usually slower scanning, better card arrangement, or improved contrast. Next are rule errors, such as assuming a group is legal or forgetting a format-specific requirement. The remedy is a current rule card and a deliberate pre-declaration check.

Add planning errors. A planning error occurs when the route was clear but you kept a card after its useful window, failed to set a fallback, or treated a narrow draw as open-ended. The remedy is a deadline, replacement-cost check, or reversal point. Decision errors are different: you saw the relevant facts but chose a weaker option. Review the alternatives and write the tie-breaker you should use next time.

Finally, track process errors. These include playing while distracted, rushing because of the timer, continuing after a technical warning, or ignoring a self-imposed stop rule. Process errors are not proof of poor card skill. They indicate that the conditions around the hand need attention.

For each error, write four fields: label, observable fact, likely cause, and next experiment. “Planning; kept a one-card route through four turns; no deadline; test a two-turn cutoff” is better than “bad patience.” Limit the review to one or two high-value lessons. An oversized list becomes another distraction.

Review categories over several hands. If reading errors cluster on a small screen, change the display. If rule errors appear after switching formats, use a rule card. If process errors appear late in sessions, shorten the session or add a break. The taxonomy is not a score of your character. It is a map from evidence to a manageable change, which is exactly what a useful review should provide.

Avoid creating a separate label for every unusual event. Four or five stable categories make patterns visible across time; too many labels hide the pattern in administration. If an error fits two categories, choose the one that changes the next action and mention the other briefly. Reclassify later if repeated evidence shows that process pressure was the deeper cause.

Keep the taxonomy private and generic if it is stored digitally. The record is for learning, not for exposing table participants or account information.