Federal Acquisition Regulation (FAR) Part 15: Contracting by Negotiation (RFP Rulebook)

FAR Part 15 is the heart of most federal RFP-style procurements. When an agency wants to evaluate offers based on more than just lowest price—think technical approach, staffing, schedule confidence, past performance, risk posture, and management plan—Part 15 is typically the framework used. For bid managers, proposal teams, and capture leads, Part 15 is the “how the government decides” playbook: it governs how proposals are evaluated, when the government can talk to offerors, how tradeoffs are justified, and how pricing is analyzed before award.

What FAR Part 15 covers in plain English

Part 15 primarily covers competitive negotiated contracting, including:

• Source selection rules (how the government compares and ranks proposals)
• Best value decision-making (tradeoffs vs lowest price technically acceptable)
• Proposal evaluation concepts and fairness expectations
• Exchanges with offerors after proposals are received (clarifications, communications, discussions)
• Contract pricing and proposal analysis (price analysis, cost analysis, subcontract pricing considerations, profit)
• Negotiation documentation (what contracting officers must document in the file)
• Unsolicited proposals (how agencies may handle proposals not requested in a solicitation)

In practical terms: Part 15 is why two “compliant” bids can receive different outcomes—because Part 15 allows agencies to choose the offer that represents the best overall value, not just the lowest number.

FAR Part 15’s most important concept: the Best Value Continuum

Part 15 introduces the best value continuum, which includes two common selection approaches:

Tradeoff (Best Value Tradeoff)

A tradeoff process allows the government to award to an offeror that is not the lowest priced when the higher-rated proposal offers benefits that justify paying more. This is where narrative and proof matter: risk reduction, execution plan credibility, staffing quality, schedule realism, and past performance relevance can legitimately outweigh a price delta.

LPTA (Lowest Price Technically Acceptable)

LPTA is used when the government expects best value from selecting the lowest-priced proposal that meets minimum requirements. No tradeoffs are permitted. If the requirement is clearly defined and performance risk is low, LPTA can be a faster method. For proposal teams, this means compliance discipline and avoiding “unacceptable” findings are everything—because price becomes the primary differentiator after acceptability.

Proposal evaluation and “what you say must match how they score”

Part 15 requires that evaluation factors and significant subfactors (and their relative importance) be clearly stated in the solicitation when using tradeoffs. This creates a simple but powerful proposal rule: organize your response exactly the way the government evaluates. If the evaluation factors are Technical, Past Performance, and Price—your proposal structure, headings, and proof should mirror that logic. A strong Part 15 proposal is one where reviewers can quickly connect your claims to the evaluation factor language with minimal interpretation.

Exchanges with offerors: clarifications vs communications vs discussions

One of the most misunderstood areas in Part 15 is what the government can ask after proposals are submitted. Part 15 outlines a spectrum of exchanges:

• Clarifications: limited exchanges when award without discussions is contemplated (usually minor points, not proposal rewrites).
• Communications: exchanges that may occur before establishing the competitive range, often to address certain issues without opening full discussions.
• Discussions: negotiated interactions after the competitive range is established, typically involving addressing deficiencies and significant weaknesses and giving offerors a fair chance to revise.

For bidders, the takeaway is operational: treat every post-submission question as a controlled negotiation moment. Have a pre-built internal workflow for rapid responses, version control, and traceability—especially when addenda or shifting requirements appear.

Part 15 pricing and “fair and reasonable” isn’t optional

Part 15’s contract pricing rules focus heavily on ensuring the final agreed-to price is fair and reasonable. Contracting officers can use multiple analytical techniques, depending on the acquisition—ranging from straightforward price comparisons to deeper cost analysis approaches when appropriate. Subcontract pricing, profit considerations, and documentation expectations all sit under this umbrella. For contractors, this changes how you should price and justify:

• Keep assumptions explicit and consistent across technical and commercial volumes
• Back up major cost drivers with logic that can withstand scrutiny
• Ensure subcontractor quotes and allocations are defensible and current
• Avoid hidden risk-loading that contradicts your “low risk” technical narrative

Part 15 proposal playbook: how bid teams should operate

Use this as a field-tested approach to stay aligned with Part 15 realities:

1) Build a Compliance-to-Evaluation Map (before drafting)

Create a single master tracker that includes:

• Mandatory requirements (every “shall” and submission instruction)
• Evaluation factors and subfactors (exact phrasing from the RFP)
• Your planned proof artifacts (past performance references, staffing resumes, plans, schedules)

2) Write for evaluator speed

Part 15 awards are influenced by how quickly evaluators can validate strength. Use:

• Short, verb-led headings aligned to subfactors
• Evidence-first writing (what you did, what it achieved, why it reduces risk)
• Clear cross-references between approach, staffing, and schedule

3) Be “discussion-ready” from day one

Maintain an internal log of:

• Potential ambiguities in the RFP
• Assumptions you used
• Pricing sensitivities and alternates
• What you can concede or clarify without damaging compliance

4) Make pricing match the story

If your technical volume says “low risk, proven approach,” your price volume can’t look like a speculative bet. Part 15 pricing scrutiny punishes misalignment.

FAR Part 15 Checklist (copy-paste)

• Confirm whether the RFP is tradeoff or LPTA and tailor strategy accordingly
• Mirror the evaluation factors in proposal structure and headings
• Create a master compliance matrix and lock submission requirements early
• Prepare a clarification/discussion response workflow (roles, SLAs, version control)
• Build a pricing rationale pack that supports “fair and reasonable” analysis
• Validate subcontractor pricing, scope alignment, and flowdowns
• Document assumptions and ensure they are consistent across volumes
• Plan for addenda: change log, impact analysis, and quick re-validation of compliance

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Sources

• https://www.acquisition.gov/far/part-15 (Acquisition.gov)
• https://www.acquisition.gov/far/15.101 (Acquisition.gov)
• https://www.acquisition.gov/far/15.101-1 (Acquisition.gov)
• https://www.acquisition.gov/far/15.101-2 (Acquisition.gov)
• https://www.acquisition.gov/far/15.306 (Acquisition.gov)
• https://www.law.cornell.edu/cfr/text/48/15.306 (Legal Information Institute)
• https://www.acquisition.gov/far/15.404 (Acquisition.gov)
• https://www.acquisition.gov/far/15.404-1 (Acquisition.gov)
• https://www.acquisition.gov/far/subpart-15.3 (Acquisition.gov)