A binary Bernoulli trial
Yes and No occupy two equal outcomes, giving P(Yes) = P(No) = 1/2. This is a binary decision rule, not evidence that either answer is wise. The model assumes the two consequences are acceptable before the wheel is opened.
One decision with numbers
Imagine two friends cannot choose between a blue or green poster and agree that Yes means blue. If Yes appears, blue is selected with a pre-spin chance of 50%. In 40 fresh decisions the expected number of Yes results is 20, yet 26 Yes results would not prove bias by itself.
Assign the meanings first
A frequent mistake is asking a vague question, then treating Yes as permission for a different action than the one originally intended. Write one reversible question: for example, 'order blue tonight.' Do not use a two-outcome wheel to conceal a choice that actually has several options.
Not a consent or risk test
A random answer cannot create consent, replace medical or legal judgement, or settle an irreversible commitment. Use the wheel only after both outcomes have been made legitimate choices.
Ask a reversible question
Binary randomness is most useful when either result can be carried out without harm. 'Take the earlier train today' has a clear Yes mapping and a clear No mapping. 'Should I quit my job?' bundles money, relationships, notice, and alternatives into a single word, so a half-and-half display supplies no useful analysis. Narrowing a question often reveals that it needs facts rather than a tie-break.
Two outcomes need two acceptable plans
Suppose a couple has already checked weather and transport and merely needs to choose whether to cycle to the park. Yes can mean pack helmets; No can mean take the bus. The wheel is useful because both plans exist. It fails when No means 'do nothing' and Yes carries hidden risk. Preparation supplies the meaningful alternatives; the binary draw only selects between them.
Before asking
State the exact action represented by Yes and the exact alternative represented by No. If either wording remains unclear, the decision is not ready for a binary randomizer.
Result record
Write the completed action, not merely Yes or No, because the action is what makes a binary choice reviewable.