Error fidelity refers to how detailed and how precise transaction decline messages are. There are over 100 different and very specific reasons for why a transaction might be declined. But some payment gateways don’t provide this level of detail and instead only specify a dozen or so error types. Granular error fidelity is critical for a subscription business because the likelihood of successful payment collection can be drastically improved by customizing the collection attempts based on the exact decline reason. So, the more detailed a payment gateway is in terms of identifying why a transaction was declined, the more effective a billing system can be in terms of how best to address the decline and rectify it.