> ## Documentation Index > Fetch the complete documentation index at: https://deepline.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Evaluating an enrichment waterfall > How coverage, identity, acceptance rules, and source overlap determine whether an enrichment route is useful. An enrichment route is useful when it establishes a fact the next process can trust. Raw match rate measures a narrower thing: whether a source returned a candidate. The gap between those measures is where many waterfall comparisons become misleading. The [waterfall overview](https://deepline.com/docs/features/waterfall-enrichment.md) explains the execution mechanism. This page explains how to evaluate its business quality. ## Coverage depends on the population A provider's result on one geography, company size, or identity input does not establish its performance on another. A profile URL and an ambiguous name give sources different evidence to work with. Mixing those inputs into one coverage number can hide the segment that actually matters. An evaluation therefore needs a defined population and acceptance rule. The useful comparison is how each source performs on the same records, not which vendor reports the largest aggregate match rate. ## Identity and field validation answer different questions An address can pass an email check while belonging to the wrong person. A correctly identified person can have an address that is stale or unsuitable. Identity confidence and field validity are separate dimensions. For example, two people may share a name at related companies. A source can return a syntactically valid email without resolving that ambiguity. Promoting it into a CRM contact collapses uncertainty that the workflow has not removed. A usable result depends on the team's intended action. Researching an account can tolerate candidates that a customer-facing outreach process should send for review. The evaluation must preserve that distinction instead of treating all nonempty fields as equally useful. ## Complementary coverage matters more than duplicated coverage A second source adds value when it resolves records the first source misses under the same acceptance rule. If both return the same accepted rows, the second may provide redundancy but little incremental coverage. The distinction affects provider order. Running a broad source first can be reasonable, but a specialized source may belong earlier for a segment it handles particularly well. One global ordering need not be optimal for every input population. The same reasoning applies to validation. More checks are useful only when they resolve a meaningful uncertainty. Repeating equivalent evidence does not necessarily make an identity decision stronger. ## Outcome categories preserve the explanation An accepted result, an ordinary miss, a rejected candidate, a conflict, and a provider error should remain distinguishable in the evaluation. They imply different limits and different possible improvements. A miss may justify another source. A conflict may require a precedence policy. A failed request says little about coverage until the access or execution problem is understood. Combining them into a single failure percentage loses the reason the route did not produce an accepted result. Deepline's maintained Plays expose their own result and attempt contracts. They do not automatically know the evaluator's ground truth or define the team's CRM acceptance policy. Those criteria must be supplied by the workflow and review process. ## The evaluation itself has limits A dated, reviewed sample estimates performance on that population. It does not freeze future data quality or guarantee delivery to an email address. Changes in sources, input mix, and acceptance policy can change the useful result rate. [Enrichment cost](https://deepline.com/docs/guides/enrichment-cost-optimization.md) adds the economic view: accepted coverage and the cost of reaching it need to be considered together. ## Apply this understanding * [Run and evaluate a waterfall](https://deepline.com/docs/guides/waterfall-enrichment-claude-code.md). * [Validate an incoming file](https://deepline.com/docs/guides/validate-incoming-csv-files.md). * [Inspect the prebuilt contracts](https://deepline.com/docs/plays/catalog.md). This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.