The model (Figure 6.5) assumes a closed system without migration.

This is because people are not passive, as the model assumes.

The model assumes that the players do not change their rating.

This model assumes that people are selfish in the narrow sense.

Alex's model could assume any one of them, and still make predictions.

This model assumes that not all potential habitats will be used by the salmon.

And so the model assumes that there was no further transmission of the disease to humans after 1996.

So far the model has assumed very few products and/or cost elements.

However this model assumed much greater energy efficiency than the other models and so less electricity was required.

The merging model has assumed responsibility for the security of the system.