Warehouse, lake, lakehouse, fabric and mesh compared by data flow, ownership, governance and consumption, with guidance on when to pick each.

How payers review whether care is medically necessary (prospective, concurrent and retrospective review) and why it leads to denials.

When pre-approval is required, how a request moves between provider and payer, and why delays and denials happen.

The three code sets on every claim (diagnoses, procedures and supplies), plus modifiers and how codes link together.

A practical guide with lab, office-visit and durable medical equipment examples, and why Medicare and commercial payers treat the code sets differently.

How payers and repricers apply contracted rates, fee schedules and DRGs to billed charges, and what that means for providers and patients.

What a provider network is, how payers contract with providers, and why the same visit can cost very different amounts depending on network status.

How each plan type trades off cost, choice of provider and referral rules, with examples of which one fits which patient.

Why insured patients still get bills: a worked example of how a claim's allowed amount is split between the plan and the patient.

A hands-on walkthrough of Safe Harbor and Expert Determination, then a Python framework that de-identifies and re-identifies PHI in 837 and 835 files.