The National Estuarine Eutrophication Assessment/ASSessment of Estuarine Trophic Status (NEEA/ASSETS) is a screening model that uses a Pressure-State-Response framework to assess eutrophication.

 Overall human influence (OHI) on development of conditions (Pressure)

 Overall eutrophic conditions (OEC) within a water body (State)

 Determination of future outlook (DFO) for conditions within the system (Response)

Reliability of the assessment is determined in an initial data evaluation stage where the completeness and reliability of the data is determined based on spatial and temporal sampling scales. Analytical methodology is also taken into account.

The OEC, OHI and DFO are combined to provide a single eutrophication assessment rating for an estuary in one of five categories: high, good, moderate, poor or bad. These categories are colour-coded following the convention of the EU Water Framework Directive (2000/60/EC), and provide a scale for setting eutrophication related reference conditions for different types of transitional waters.