Table 2. List of files with variables (selective).

Files	Variables	Common variables
General information	- Beneficiary ID, age, gender, insurance number, type of insurance, date of review, provider ID, indicators for inpatients/outpatients, indicators for types of providers	Billing statement code, date & year of receipts
	- Operation related to primary diagnosis
	- Specialty
	- Dates of treatment, dates of dispensation
	- Primary diagnosis, secondary diagnosis, surgery, area of provider's practice
	- No. of days undergoing care, first visit to a physician, dates of encounter, date of admission, date of discharge
	- No. of days of supply for prescriptions, quantity of prescriptions, special codes for different out-of-pocket costs
Healthcare services	- Procedures, inpatient prescriptions, diagnostic tests, treatments
	- Operation, injection, and examination
	- Unit price, quantity per day, days of supply, etc
Diagnosis	All diagnoses
Outpatient prescription	Quantity per time, quantity per day, days of supply, drug code, unit price, amount, date of prescription
Drug master	Drug code, date of starting (and terminating) coverage, drug name, unit, manufacturer, channel of administration, coverage, unit price, etc
Providers information	Provider ID, location, zip code, name of providers, types of provider, address, date of open, no. of business, no. of beds, etc

ID = identification.