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Interest-Based Negotiation

Most negotiation prep fixes on positions - what each side says it wants - and then plans to fight position against position, splitting the difference at the end. Interest-based negotiation refuses that frame. It models the counterparty (the move no solo decision method makes): it surfaces the interests behind the positions on BOTH sides of the table, anchors the accept-or-walk decision on a named, valued best alternative away from the table rather than on hope or the opening offer, and creates value across differently-valued issues before dividing it. The durable move is not the five-element checklist. It is treating the deal as a structured decision against an explicit alternative, with the counterparty's interests and alternatives modeled, not assumed. The output is a negotiation preparation map: positions and interests for both parties, the best alternative and reservation point, the zone of possible agreement, options for mutual gain built from valuation differences, the legitimacy standards a division can appeal to, and the follow-through an agreement must carry. It is explicitly preparation deskwork - not a script for the live table.

This method consolidates three formulations as one: Fisher and Ury's principled negotiation (separate the people from the problem, interests not positions, options for mutual gain, objective criteria, the best alternative as power anchor); Raiffa's decision-analytic skeleton (reservation prices, the zone of possible agreement, the efficient frontier); and the Mutual Gains Approach (prepare, create value, distribute value, follow through - the follow-through adopted here as a map section). The mechanisms coincide; the brand vocabulary is set aside for the descriptive move.

When to Use

• Agreement is required from a party you do not control, and more than one issue is in play - salary packages (pay, start date, scope, remote terms), vendor and partnership contracts (price, term, service level, exclusivity), cross-team resource conflicts, licensing and acquisition terms, multi-party public disputes.
• A position fight has hardened and no one has checked whether the interests are actually opposed. This is the documented failure mode the interests step exists to attack.
• A consequential negotiation is upcoming and the discipline is worth it on its own: naming and valuing your best alternative converts "I need this deal" into a priced choice.

When NOT to Use

• Do not manufacture win-win on a genuinely single-issue, one-shot, distributive haggle. With one issue and no relationship there is nothing to logroll; only the best-alternative, reservation-point, and zone apparatus applies. Inventing imaginary integrative options on a pure price split is theater. Report the honest zone-only read instead.
• Do not assume good faith by default. Against a hard bargainer acting in bad faith, naive openness about interests is exploitable information disclosure (White, 1984, the standard critique of Getting to Yes). Mark which interests are safe to reveal and which to hold; interest disclosure is a calibrated act, not a default.
• Do not use it when there is no counterparty. A choice you alone control is option evaluation, not negotiation - route to think-decision-option-review or think-expected-value-decision-tree.
• Do not emit an accept-or-walk recommendation without a named, valued best alternative. The walk-away anchor is the load-bearing element; without it the structure floats. If no alternative exists, the first move is to develop one (or to recognize you are deciding under duress), not to bargain.
• Do not present the package as validated procedure. The component mechanisms are evidenced; the five-element procedure as a package is practitioner codification (see evidence/dossier.md). The map improves the decision's structure; it does not guarantee outcomes.
• Do not value-create your way around a power asymmetry. When one side can walk costlessly and the other cannot, the honest output is sometimes "improve your alternatives or do not enter," not a clever package.

Instructions

When asked to prepare for a negotiation or to build a negotiation strategy, follow these steps:

1. Confirm there is a counterparty and more than meets the eye. State the deal in one line and the parties whose agreement is required. If there is no counterparty, stop and route to a solo decision skill. If it is genuinely single-issue and distributive, say so and run the zone-only path (steps 4-5 only), refusing to manufacture integrative options.
2. Separate positions from interests, on both sides. List each party's stated position, then the underlying interests it serves. Rank your own interests. Infer the counterparty's interests and flag each inference's confidence. For every interest of yours, mark whether it is safe to disclose or should be held - never assume good faith by default.
3. Name and value your best alternative; derive your reservation point. Identify the best alternative to a negotiated agreement (what you do if this deal collapses), value it honestly, and set the reservation point it implies - the worst deal still better than walking. If your alternative is undefined, name developing it as the first action and do not emit an accept-or-walk call yet.
4. Estimate the counterparty's alternative and bound the zone. Infer the counterparty's best alternative and reservation point (with confidence flags), then state the zone of possible agreement - the interval between the two reservation points. If the zone is unknown or negative (no overlap), say so plainly; that is a valid and important output.
5. Invent options for mutual gain across differently-valued issues. Find issues the two sides value differently and build candidate trades - what is cheap for you and dear to them against what is dear to you and cheap for them. Create value before dividing it. (Skip on a genuine single-issue distributive case; there is nothing to trade.)
6. Name the objective criteria for dividing value. List the legitimacy standards a division can appeal to - market rate, precedent, an independent appraisal, an industry benchmark - that both parties could accept, rather than relying on willpower or splitting the difference.
7. Specify the follow-through. Name the monitoring, milestones, and dispute-handling an agreement must carry so that "yes" survives contact with reality (the Mutual Gains contribution).
8. Emit the negotiation preparation map per references/TEMPLATE.md, carrying the evidence caveat. Keep it to preparation; decline to script live-table tactics or manipulative moves.

Output Format

Use the template in references/TEMPLATE.md. The deliverable is the filled negotiation preparation map - parties and positions, both-sides interests with confidence and disclose-or-hold flags, the best alternative and reservation point, the zone of possible agreement, options for mutual gain, objective criteria, and follow-through - not a prose essay. The pre-printed evidence-caveat line ships in the artifact. Never script the live table.

Quality Checklist

Before finalizing, verify:

• [ ] A counterparty is confirmed; if there is none, the run routed to a solo decision skill instead.
• [ ] Positions are separated from interests on BOTH sides; the counterparty's interests are inferred with confidence flags, and each of your interests is marked disclose or hold.
• [ ] A named, valued best alternative and the reservation point derived from it are present; no accept-or-walk recommendation is made without them.
• [ ] The counterparty's alternative is estimated and the zone of possible agreement is stated - including an explicit "unknown" or "negative / no overlap" read when that is the truth.
• [ ] Options for mutual gain are built from genuine valuation differences - or, on a single-issue distributive case, the map honestly reports a zone-only read with no manufactured win-win.
• [ ] Objective criteria for dividing value and the follow-through commitments are both named.
• [ ] Which interests are safe to disclose and which to hold is marked; good faith is not assumed by default.
• [ ] No overclaiming: the evidence is practitioner-grade with moderate-grade components, transferred from human studies; claim a preparation aid, not a guaranteed better outcome (see evidence/dossier.md).

Evidence

Tier P (governing). The component mechanisms carry genuine moderate (M) experimental support on human dyads - the fixed-pie misperception is real and pervasive (Thompson and Hastie 1990; Thompson and Hrebec 1996, a review of 32 experiments on lose-lose agreements), alternatives confer measurable power on own and joint outcomes (Pinkley, Neale and Bennett 1994), and integrative behavior raises joint outcomes under prosocial motive plus high resistance to yielding (De Dreu, Weingart and Kwon 2000, a meta-analysis of 28 studies; Pruitt and Lewis 1975). But the prescriptive package itself - the five Fisher-Ury elements, the four Mutual Gains steps - has no controlled validation as a package, and training evidence does not isolate it (Movius 2008 limited and mixed; ElShenawy 2010 moderate effects for training generally). Per this library's conservative-split rule the governing grade is the lower half, P; grading M would launder component evidence onto the procedure. All evidence is transferred from human dyads; nothing validates this preparation move agent-side (LLM benchmarks such as Bianchi et al. 2024, NegotiationArena, measure bargaining outcomes, not this prep procedure). The skill ships as a preparation aid with hard when-NOT walls, never as a guarantee of a better outcome. Full grading, sources, and caveats: evidence/dossier.md.

Examples

See references/EXAMPLE.md for a completed negotiation preparation map on a real decision. </content>