Podcast Summary: Más de uno – "Cómo se cuentan las epidemias"

Host: Carlos Alsina (A), Santi García Cremades (B - matemático invitado), Colaborador/a (C)
Date: December 11, 2025
Podcast: Onda Cero

Overview

This episode of "Más de uno," hosted by Carlos Alsina, features mathematician Santi García Cremades. The main topic is how epidemics—specifically, the flu—are quantified and reported in Spain. The episode blends humor and clear explanations to make concepts about public health statistics and mathematical reasoning around epidemics more accessible to listeners.

Key Discussion Points & Insights

Countdown and Numbers in Everyday Life

• The episode opens with playful banter about the countdown to the end of the year and superstitions about mentioning holidays too early. (00:03-00:36)
• Santi transitions from festive numbers to more serious statistics: flu infection rates.

Listener Math Challenge Recap (02:00)

• Santi reviews last week’s math challenge: arranging digits in a 2x2 matrix so rows and columns add up to particular sums. Listener José Carlos from Málaga provides the correct answer.
  • Notable moment: (02:12)
    José Carlos: “La matriz se compone la primera fila de los dígitos 1 y 4 y la segunda fila sería 3 y 2.”

How Are Epidemics Counted? (02:43–04:39)

Proportions and Visualization

• Flu Data Update:
  Santi shares current stats: “Estamos en unos 275 casos de gripe por cada 100.000 habitantes.” (02:46)
• Why cases are reported as "per 100,000 inhabitants":
  • Santi explains this helps make comparisons between places and is easily visualized, like imagining a full football stadium. (03:28)
    • Quote: “Estamos obsesionados con los estadios de fútbol... Es para mezclar densidades... Así podemos comparar pueblos y ciudades.” (03:28)
  • When numbers reach 1,000 per 100,000 (1% infection rate), that’s cause for alert.

Clear Communication in Health Stats

• Comparing reporting methods, Santi points out that “per 100,000” makes it easier to discuss regional differences, visualizing infection rates in settings big and small.

Understanding Percentage Changes (04:39–05:35)

• Santi demystifies confusing headlines about spikes in infection rates.
• Percent Increase Algorithm:
  • “Cuando algo sube un cien por cien, entendemos que se ha duplicado... Pero cuando sube más del 100%... le quitamos los ceros y le restamos uno. Ese es el número por el que se multiplica.”
  • Example:
    • 250% increase: drop the zeros (2.5), add 1 → 3.5. The new amount is 3.5x the original. (04:58)
    • Santi pokes fun at exaggerated stats: “Nadie entiende que es aumentar un 1.200%... hay que aplicar el algoritmo.” (05:29)

New Listener Math Challenge (05:35–07:12)

• Santi presents a new puzzle: Find four digits so that, when arranged in order, the absolute difference between each consecutive pair is unique and as large as possible.
  • Clarification: “Distancia es la diferencia entre una cifra y otra... Y esa distancia tiene que ser máxima.” (06:03)
  • Example: With 1-2-4-7, the differences are 1, 2, and 3—each unique.
  • Listeners are encouraged to submit answers for an honorary prize.

Notable Quotes & Moments with Timestamps

• Banter about holiday countdowns:

  • C: “De la Navidad no se puede decir nada hasta el 22...” (00:27)
  • A: “Ni digas Papá Noel, ni digas los peces. Nada, nada.” (00:33)

• Explaining epidemic statistics:

  • B: “Esta proporción siempre me ha parecido súper curiosa... Suena muy de salud pública.” (02:46)
  • B: “Cuando llegamos a 1.000 por cada 100.000... es un 1% de la población.” (03:25)

• Percentage change demystified:

  • B: “Cuando algo sube un cien por cien... eso con el sueldo no falla. Te subimos un 100%... Eso es el doble.” (04:55)
  • B: “Nadie entiende que es aumentar un 1.200%... hay que aplicar el algoritmo.” (05:29)

• Introducing the new challenge:

  • B: “La distancia tiene que ser máxima entre esos números... y que sea diferente siempre.” (06:04)

Timestamps for Key Segments

• Holiday Bans & Festive Numbers: 00:03–00:38
• Math Challenge Solution: 01:53–02:40
• Flu Stats and Counting Epidemics: 02:43–04:39
• Percentage Increase Clarified: 04:39–05:35
• New Math Challenge (Listener Riddle): 05:35–07:12

Conclusion and Tone

The episode masterfully uses everyday references (holiday countdowns, football stadiums) and humor to explain the science and math behind epidemic reporting. Santi García Cremades provides concise, relatable ways to understand often-confusing percentages and health statistics, closing with an engaging puzzle for the audience.

Tone: Informal, humorous, and educational, reflecting Alsina’s and Santi’s rapport and commitment to making complex topics entertaining and accessible.