Every name picker says it is random. The word is free to print and impossible to check by eye — a wheel that favours the top of your list looks exactly like one that does not. The only way to know is to draw a very large number of times and count. So we took the exact selection code that runs inside WheelMigo, ran it 7,000,000 times over a list of seven names, and ran a popular shortcut the same 7,000,000 times next to it.
How we tested
Both methods drew from the same seven-name list, 7,000,000 times each, and we tallied how often each name won. Method one is WheelMigo's real algorithm: ask the browser's crypto.getRandomValues for a 32-bit number, throw away the small leftover range that would not divide evenly (rejection sampling), and keep the remainder. Method two is the tempting one-liner a quick build often uses: take a single random byte, 0 to 255, and use its remainder modulo the number of names. Same list, same number of draws, same machine — only the selection method differs, so any gap between them is the method, not luck.
The result: WheelMigo lands even, the shortcut does not
A perfectly fair picker gives each of seven names 14.29% of the wins. Here is what 7,000,000 draws produced for each method (percentages of all wins):
| Name (of 7) | WheelMigo | Naive byte % n | Even target |
|---|---|---|---|
| Name 1 | 14.28% | 14.45% | 14.29% |
| Name 2 | 14.28% | 14.44% | 14.29% |
| Name 3 | 14.30% | 14.47% | 14.29% |
| Name 4 | 14.30% | 14.45% | 14.29% |
| Name 5 | 14.27% | 14.08% | 14.29% |
| Name 6 | 14.28% | 14.05% | 14.29% |
| Name 7 | 14.29% | 14.06% | 14.29% |
WheelMigo's biggest gap from a perfect one-in-seven was 0.015 of a percentage point — ordinary sampling noise that shrinks further the more you draw. The shortcut's biggest gap was 0.24 of a point, about sixteen times larger, and it was not noise: names 1 through 4 were consistently high and names 5 through 7 consistently low. A name in the favoured group came up 2.78% more often than one in the unfavoured group, every run.
Where the shortcut's bias comes from
A byte holds 256 values. Divide 256 by 7 names and you get 36 remainder 4: the numbers 0, 1, 2 and 3 each land 37 times across the byte's range, while 4, 5 and 6 land only 36 times. Map those remainders onto your list and the first four names inherit the extra chance. It is invisible on any single spin and on any short session — but over a school term of daily cold-calls, or a raffle with hundreds of tickets, "the top of the list wins a bit more" is exactly the kind of quiet unfairness a picker is supposed to remove.
The trap: with eight names the same shortcut looks flawless
We reran the shortcut with eight names instead of seven. This time it was even — its largest gap was 0.02 of a point, as clean as WheelMigo's. The reason is arithmetic: 256 divides by 8 exactly, so there is no leftover to favour anyone. That is the real lesson. The same picker can be biased with six or seven names and perfect with eight, and nothing on screen tells you which list you are in. Fairness you cannot see is not fairness you can trust; it has to be built into how the draw is made, not left to the size of today's list.
What WheelMigo does instead
Rather than a single byte, WheelMigo draws a full 32-bit number — a range of about 4.29 billion — and discards the tiny sliver at the top that would not divide evenly before taking the remainder. At seven names only four of those 4.29 billion values fall in the discard zone, so fewer than one draw in a billion is ever thrown away; across our 7,000,000 draws, not one was. That is why every name sat on its exact share regardless of how many names were on the list. The mechanism, step by step, is in “How WheelMigo actually picks a name”; this article is the measurement that backs it up.
Why a fraction of a percent matters
For one spin at a party, none of this matters. For a draw that repeats — a teacher choosing who answers every day, a giveaway that runs for weeks, a rota that decides turns — a 2.78% standing advantage compounds into real, noticeable unevenness, and it always favours the same people. That is the whole reason to use a dedicated picker instead of guessing, and the reason the selection method, not the animation, is the part worth checking. Honest boundary, unchanged: WheelMigo is a browser tool for casual and classroom draws, not a certified, audited service for regulated prizes or lotteries.