Lottery Guide

Random draw bias — 3 ways winners turn out unfair

Run a raffle with a copy-paste randomizer three times and you can end up with three different-looking results that are all quietly broken. The unfairness is rarely obvious. It hides in duplicates, entry order, and the seed. Here is how each one rigs your draw and how to write it out.

1. Duplicate names gas the odds

If the same person appears on a list twice — once as "Chris" and once as "Chris " with a trailing space — you just doubled their odds. A fair draw needs consistent, de-duplicated entries first. The lottery mode strips blank lines and collapses true duplicates before a single pick, so typos and double-entry can't silently inflate a ticket.

2. Without replacement vs with replacement

Drawing five winners should not let one lucky name pop up twice — unless you intentionally sold them five entries. "Without replacement" removes each winner from the pool after the pick; "with replacement" throws them back in and re-rolls. For a standard multi-winner prize draw, without replacement is the fair default. Decide the rule before the draw, then make the tool follow it.

3. The swimming-pool seed

A draw seeded by wall-clock time is re-runnable: know the seed, replay the draw, predict the winners. This is exactly what a good randomizer refuses. Our generator draws from the OS cryptographic entropy pool, so there is no seed to replay. Combined with a shuffle that reorders every ticket, the output cannot be gamed by watching the clock.

Ticket math in one line

Each person's chance is their ticket share, not their row position. Position bias — where entries near the top of your list "feel" luckier — is pure illusion once the list is shuffled. Roll the lottery draw, watch the shake animation land, and screenshot the result: an auditable record of a fair draw beats memory every time.