In 2012, behavioral economists Michael Norton, Daniel Mochon, and Dan Ariely ran an experiment. They had people assemble IKEA boxes, fold origami cranes, and build LEGO figures, then asked both builders and non-builders to value the same objects. Builders valued their creations 63% higher than observers valued identical ones. The researchers named it the IKEA effect. Service sellers who understand this stop sending finished proposals and start building them with the buyer in the room.
Why a Finished Proposal Has a Valuation Problem
When you send a polished, fully-formed proposal to a buyer, you’ve done all the thinking. The scope is clear. The timeline is set. The price is final. From a professional standpoint, this feels right, thorough, authoritative, complete.
From a psychological standpoint, you’ve made a critical error. The buyer received something. They didn’t create anything. And according to the IKEA effect research, things we receive are valued far less than things we help build, even when the objects are objectively identical.
The buyer looks at your proposal as a vendor document. They interrogate it. They send it to procurement. They shop it against competitors. They didn’t build it, so they don’t own it, and they don’t feel responsible for making it work.
The IKEA Effect Research: What It Actually Proves
Norton, Mochon, and Ariely’s 2012 paper, “The IKEA Effect: When Labor Leads to Love”, demonstrated three consistent findings:
Labor increases valuation. Participants who assembled objects valued them more highly than those who received pre-assembled equivalents, regardless of assembly quality.
Completion matters. Partial effort that doesn’t result in a completed product does not trigger the effect. The buyer needs to see their input reflected in the final output.
The effect is independent of skill. Inexpert builders still overvalued their creations. In sales, this means buyers don’t need to be domain experts for their input to increase their attachment to the solution.
The implication is direct: any discovery call that ends with “we’ll send you something” and results in zero buyer input into the design has squandered the IKEA effect entirely.
A buyer who co-ranks priorities and names their core metric is not just a more informed buyer, they’re a partial author of the plan. That authorship increases close rate and reduces ghosting.
Three Co-Design Moves for Any Discovery Call
You don’t need to restructure your entire sales process. These three moves fit inside a standard 45-60 minute call and transfer partial ownership to the buyer without sacrificing your expert authority.
Move 1: The Priority Ranking
Present three outcome areas your work typically addresses (e.g., speed to close, deal size, forecast accuracy). Ask: “If we could only move one of these dramatically in the first 90 days, which one would have the most impact on your business?”
Their answer becomes the first section of your scope. When they read the proposal, they see their priority reflected back. They built that structure. The effect activates.
Move 2: The Problem Naming
Ask the buyer to describe the core problem in their own words. Write it down verbatim. Then open your proposal summary section with their exact language, in quotes or very closely paraphrased.
When they read it, they recognize their own thinking. The proposal reflects their diagnosis. They’re not reading a vendor’s interpretation of their problem; they’re reading their own problem back. Ownership increases sharply.
Move 3: The First-Milestone Decision
Rather than proposing a timeline, ask: “What would need to be true in the first 60 days for this to feel like it’s working?” Use their answer as the anchor for your Phase 1 deliverable.
The buyer now has a personal stake in Phase 1 succeeding. They defined success. They’ll advocate internally for the project to get greenlit because their credibility is now tied to the outcome they named.
Structuring the Proposal to Make Co-Design Visible
The IKEA effect requires that buyers see their contribution in the final product. If they gave you input during the discovery call but your proposal looks identical to what you’d have sent anyway, the effect doesn’t transfer.
Make their input explicit:
- “Based on your priority ranking, we’ve structured Phase 1 around forecast accuracy rather than deal volume.”
- “You described the core challenge as [their exact words], our scope is designed specifically to address that.”
- “Per your 60-day milestone, we’ll deliver the initial framework by Day 45 with a checkpoint to validate direction.”
Each of these sentences tells the buyer: your input shaped this plan. You helped build it. The valuation shift follows.
When Buyers Don’t Want to Co-Design
Some buyers, particularly in enterprise or procurement-led evaluations, expect a finished proposal submitted against a fixed brief. In those contexts, full co-design is inappropriate.
But even in RFP situations, you can run a modified version. Before submitting, ask one question that their answer visibly informs: “Is there a section of the brief that you’d want us to prioritize in the executive summary?” Whatever they name, lead with it.
The goal isn’t to get buyers to do your work. It’s to transfer even one decision to them before the document lands.
The Long-Term Effect: Internal Champions
The IKEA effect has a second-order benefit that matters in complex sales. When a buyer co-designs your solution, they become its internal champion. They don’t just prefer your proposal, they advocate for it in rooms you’re not in.
In a committee decision, the person who contributed to your scope is the person who says “this proposal is the most aligned with what we said we needed”, because it actually is, because they helped define it.
Co-design converts buyers into advocates. In deals with three or more internal decision-makers, that internal advocacy is often the deciding factor.
