Options are alternatives; try to maximize them. Look at interests, not positions, to expand options. Invent first; evaluate later.
The purpose of identifying each side’s interests is to see if you can devise options to satisfy them. Inventing options for mutual gain is the negotiator’s greatest single opportunity. Effective negotiators do not just work on the basis of givens or a fixed pie. It makes sense to explore whether it will be possible to expand the pie. While it may not be possible for each side to obtain its positions, it may be possible to satisfy its interests. It is often a mistake to stick to just one position. Considering a range of options helps generate new possibilities. Invent options first-- evaluate later. Don’t lose the value of creative thinking.