A Revenue Assurance Strategy should address: 

Products / services / revenues analysis
Revenue loss risk assessment
Establishment of Key Performance Indicators (KPIs)
End to end process control environment
Data integrity
Suspense / error file management
Debt
Collections
Fraud
Performance reporting against KPIs

Our definition of Revenue Assurance

Accurately billing for all transactions, products and
services provided, in accordance with tariffs
and contracts whilst managing fraud to acceptable
levels and collecting all due revenue.