FAR Part 15 Explained (Contracting by Negotiation)

What is FAR Part 15?

FAR Part 15 governs contracting by negotiation—the process agencies use to evaluate proposals using stated factors, compare offerors, potentially conduct discussions, and make a best-value award (often through tradeoff).

If you’re responding to an RFP with Section L (Instructions) and Section M (Evaluation), there’s a strong chance FAR Part 15 is driving the structure, terminology, and evaluation mechanics.

Why FAR Part 15 matters for proposal writers

• It defines how agencies can do best value decisions (tradeoff vs LPTA in other frameworks).
• It governs communications, clarifications, and discussions (aka what the government can/can’t ask you).
• It shapes competitive range decisions and what triggers proposal revisions.
• It’s the backbone of “why did we lose?”: because the evaluation must follow the stated factors and FAR rules.

Section L and Section M (the proposal battlefield)

Section L: Instructions to Offerors

Section L tells you how to write and submit the proposal—format, page limits, volumes, required attachments, and what must be included for each factor.

Section M: Evaluation Factors

Section M tells you how you’ll be scored—evaluation factors, subfactors, relative importance, rating methodology, and the best-value tradeoff approach.

Rule of thumb: If Section L requires it but Section M doesn’t evaluate it, you still must comply (or risk noncompliance). If Section M evaluates it but Section L doesn’t clearly request it, you still should address it (or risk weakness).

Key FAR Part 15 concepts (plain English)

Best Value vs Lowest Price

Under FAR Part 15, agencies often use best-value tradeoffs—meaning a higher-priced proposal can win if its technical value justifies the premium (as defined in the RFP). This is in stark contrast to LPTA (Lowest Price Technically Acceptable) where the lowest-priced proposal wins if it meets the minimum requirements. In those cases, the government wants the cheapest solution that gets the job done. It may not be the best product or service, but it satisfies their desire to look good for audits.

Tradeoff Process

Tradeoff means the government compares strengths/weaknesses and price to decide which proposal offers the best overall value. Your job is to create “discriminators”—credible, evaluable reasons to pick you.

Communications vs Clarifications vs Discussions

• Communications: Early exchanges to enhance understanding, often before competitive range.
• Clarifications: Limited Q&A that generally does not allow major proposal revisions.
• Discussions: More formal back-and-forth that typically results in Final Proposal Revisions (FPRs).

Competitive Range

Agencies may establish a competitive range where only the most highly rated proposals proceed into discussions. If you’re out of range, you’re been effectively eliminated.

Past Performance (the silent killer)

Past performance is frequently weighted heavily and can be subjective. A clean mapping from RFP scope → relevant projects → outcomes reduces evaluator effort and improves confidence.

Common FAR Part 15 proposal mistakes

1. Ignoring compliance mechanics (missing a required doc, form, or instruction).
2. Writing “marketing copy” instead of evaluable proof (no metrics, no process, no traceability to the factor).
3. Not matching the evaluation structure (your headings should mirror Section M).
4. Weak discriminators (nothing that creates a defendable tradeoff).
5. Past performance not “relevant” enough (wrong size/scope/complexity).

How to use FAR Part 15 to win more often

• Build a compliance matrix from Section L (submission requirements) and Section M (evaluation requirements).
• Use headings that map 1:1 to evaluation subfactors.
• Create 2–3 measurable discriminators per major factor (speed, risk reduction, quality, past performance relevance, staffing continuity, tooling).
• Convert claims into proof: process + artifacts + metrics + controls.

FAQ

Is FAR Part 15 always used when there’s a Section L & M?

Often, but not always. Many negotiated procurements follow Part 15 concepts even when another part technically applies. The RFP will usually signal the framework in the instructions and clauses.

What’s the fastest way to avoid noncompliance?

Build a compliance checklist from Section L, then verify it against all amendments. Most “instant losses” are administrative, not technical.

What’s the easiest way to improve tradeoff scoring?

Give evaluators clear, credible discriminators tied to outcomes. Make it easy to write strengths about you.

Want a faster FAR Part 15 compliance read?

Upload your RFP and instantly extract requirements, risks, and “win themes” so you can spend time writing—not hunting.