Nothing here is a survey and nothing is a forecast from historical averages. Each twin reasons through the scenario on its own and commits to an action, and the distribution is what those individual commitments add up to.
Sampling
A run does not use the whole population. It draws a sample, weighted to preserve the population’s composition, because a larger sample narrows the confidence interval with diminishing returns and rising cost. Two thousand is usually enough to separate options more than a few points apart.
Grounding
Each sampled twin carries the signals that defined it: what it has bought, where it lives, what it follows, what it said in an interview. Those signals are what make one twin tip and its neighbour not, and they are the reason a twin’s stated reasoning can be checked against something.
Resolution
A twin is placed in the scenario at the specified date and asked the question. It may deliberate over several steps, but it must finish on one member of the action space. A run is complete when every sampled twin has resolved.
Why the date matters
Twins reason from the world as it stood on the date you set. A question about delivery tipping in 2019 and the same question in 2026 reach different answers because the fee structure, the norms and the alternatives are different. Getting the date wrong is the quietest way to get a confidently wrong result.
What we do not claim
A simulation is a well-grounded estimate of how a group would behave, not a measurement of how it did. Use it to rank options, size a gap, and find the reasoning you had not considered. Do not use it as a substitute for the one real experiment you can actually afford to run.