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A program rates only the facts its rater accepts. When your book lacks a fact the rater requires, each submission the rater would accept stops as invalid_inputs:
thin is the example book with its licence dates dropped. To rate it, write each missing fact as a scenario, and rate the study with the program:

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Find the facts the book lacks

Each invalid_inputs row’s reason names the rater field it lacks, then the book column that field comes from. Count the rows by that column:
prepare derives years_licensed from each driver’s first_licensed_date, so that column is the fact to supply. A program traces book columns from its example book. A reason that ends at the rater field counts as NaN, so read the field at the start of that reason. A refused row names the carrier rule that declines it, in reason_code. program.rater.inputs marks each field the rater requires. An optional field means what its RSL says: a filed default, such as 12,000 annual miles, or an absent coverage.

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Write each assumption as a scenario

Each scenario holds one assumption. Several values of one assumption bracket its effect on the premium.

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Rate the study

baseline is the book as reported, so it keeps its unrated rows. In each scenario, 281 submissions stay unrated: 186 have a driver with a blank birth date, so the scenario leaves drivers.first_licensed_date blank, and 95 have a vehicle with a blank garaging ZIP (vehicles.garaging_postal_code).

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Compare the assumptions

dropna keeps the policies that every scenario rates, so each total compares the same policies. premium is each policy’s annual premium. A later licence age gives fewer years licensed, so the premium rises. The assumption moves the book’s total by 9.5% from age 16 to age 21.

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Check an assumption against reported facts

To check an assumption, rate the policies whose facts you hold, and compare the totals:
On these synthetic policies, a licence at age 21 gives the reported total within 0.04%. A single assumption hides the spread between drivers. Create a study fills blank facts in draws instead.