Waterfall enrichment tools look a record up in several data sources, one after another, and keep the first answer. Before you compare waterfall enrichment tools on coverage, do the arithmetic: each step only sees the records the steps above it missed, so every step you add finds less than the one before. Enter a hit rate and a price for each step in the simulator above, and it works out combined coverage and what each record found costs you.
How to read the result
A hit rate is the share a step finds of the records that reach it, not of your whole list. The cost of each record found is the figure to compare across tools, because the lookups you paid for that found nothing sit inside it.
Reorder the steps and coverage stays the same, as long as the sources miss independently. The cost moves. Billed per lookup, the top step is paid on every record you send in, so a high-priced step belongs near the bottom. Billed only when found, order matters less: a record two steps could both find is charged by whichever asks first.
Judge the bottom step on what it charges for each record it finds. If that is more than a found record is worth to you, cut it.
The independence assumption
The math assumes one source missing a record says nothing about whether the next will find it. The formulas under the simulator rest on independence and expected value, each with its source. Real sources often miss the same records, and then a real waterfall covers less than the simulator shows.
So measure each step on a sample of your own, in your order: count what it finds among the records that reached it, and enter that. Reorder the steps and measure again.
What to do next
Read each tool's pricing page for whether it bills per lookup or only when found. The two sound alike and can send very different bills.
If you would rather not keep this math current, Oneprofile does it for you: each enrichment checks its data sources in an order we set, stops at the first answer, and charges nothing for a lookup that finds nothing. To follow one contact through the sources, read how waterfall enrichment works. For what a found contact costs in credits, see what data enrichment costs.