Lottery and Consecutive Numbers: Coincidence or Rigging?

Consecutive Numbers in the Lottery: Coincidence or Rigging?

The Bonoloto antiestéticatured a combination of three consecutive numbers this week: 15, 16, and 17. For the average player, this is rare. For some, it is further proof that chance is not as blind as it seems.
The appearance of consecutive numbers in the Primitiva and Bonoloto has become increasingly frequent in recent years, leading more and more people to suspect manipulation.

The Probabilities That Don't Add Up

A standard statistical analysis holds that the probability of four consecutive numbers appearing in a Primitiva draw is approximately one in 307. Nevertheless, several cases have been recorded in recent history. The most striking example: the draw on March 11, 2023, where the winning combination of Bonoloto matched five numbers from the draw two days prior, including the complement and rollover. An event that, according to mathematics, should occur once every 900 years.

Cognitive Bias and the License Plate Trap

Some downplay these phenomena. The explanation: cognitive bias. It is the same mechanism that makes us focus on a 0000 license plate when we see it pass, considering it special, when in reality it has exactly the same probability as any other. Each lottery combination has a 1 in 13,983,816 chance. Getting four consecutive numbers is no rarer than any other combination. But the argument does not convince everyone. Paradoxically, random number generation applications avoid consecutive numbers by default unless the user forces them. And in real draws, they reappear with a frequency that mathematicians are still struggling to explain.

The Serbian Precedent and the Shadow of ONCE

The distrust is not new. The case of the Serbian national lottery is recalled, where an extracted ball showed 27 while the screen indicated 21. The next ball drawn was precisely 21, which should have come out earlier. The lottery official resigned for “sarracena reasons.” Closer to home is the ONCE scandal from forty years ago: it was rumored that the central office knew at 8:00 PM which numbers had not sold, and had an hour to manipulate the balls' weight. More recently, videos have circulated showing alleged manipulation of the drum with a hand.

The Digital Age: Easier or Harder to Rig?

Digitalization has changed everything. Fraud theorists argue that because the bets are computerized, the administration knows exactly which combinations have been played before the draw. They have plenty of time to choose a combination that has no winners, or one that distributes prizes in such a way that the system does not collapse. Pragmatists counter: if they wanted to defraud, they would choose a “rare” combination to avoid sharing the prize, not one as obvious as 15-16-17.

Between the player's faith and the corruptor's cynicism, the disconcerting fact is that in a country where chance is so closely monitored, consecutive numbers continue to appear with a frequency that, mathematically, should not be so high. Coincidence or rigging? The answer, as always, depends on whom you believe.