Healthcare Expenditures - Data on healthcare spending by type (including prescription drugs) is collected by the Centers for Medicare and Medicaid Services (CMS) and published in Health, United States. The journal Health Affairs analyzes this data in their January issue.
Consumer Price Index (CPI) - Measures price inflation. Data on prescription and non-prescription drug prices are tracked.
Research & Development - Future sales depend on a company's drug pipeline. Track R&D expenditures as a percentage of sales and compare to the industry average reported by PhRMA.