Researchers have tested this many times, in different places, over many years, and they keep finding the same result. This one is safe to trust.
A team of researchers had people build furniture. Some assembled a plain box themselves, following the instructions, doing the folding and fitting by hand. Others were given the same box already built. Then everyone was asked how much they would pay to keep their box. The people who had built theirs were willing to pay 63 per cent more for a box identical to the pre-built one. The researchers named it after the flat-pack furniture company whose products you assemble at home. The effort itself, the small labour of making the thing, created a sense of ownership and value that no amount of admiring a finished box could match.
The work you put into something makes you value it more, and that extra value is real to you but invisible to everyone else. This is why the candidate you personally found, chased, and convinced at eleven at night is the one you can no longer judge clearly, and why founders defend the hires they sourced themselves long past the point the evidence supports. Your own labour is on the scale, whether you notice it or not. When a decision involves something you built or fought for, assume you are valuing your effort as well as the thing, and ask what a stranger who did none of that work would see. Ownership alone does some of this without any labour at all, which is the endowment effect.
Source: Norton, Mochon and Ariely, The IKEA effect: when labor leads to love, Journal of Consumer Psychology, 2012. Builders bid 63 per cent more for a storage box than non-builders did for the same box already assembled.
Dan Ariely, 2010
Chapter three is the IKEA effect, built on the origami experiments behind the original paper. On why labour begets love, and why the effect disappears when people fail to finish what they started.
Every Saturday, one idea worth your time, with an honest account of how far the evidence really goes and where it stops. Free, a few minutes to read, and it leaves you with questions rather than instructions.
Draw your own card. It does not take long, and it rewards taking your time.