How do you calculate a rate per 100,000 people?
Turn counts into rates per 100,000 inhabitants so you can compare municipalities of different sizes.
Free course. Your Maestro, an AI, .
La Ceiba wants to open a new branch, and management asks for one thing: where is a business most likely to be robbed? You have the thefts from businesses reported in 2025 in the region's 18 municipalities. Ciudad Ceiba tops the list with 2,272; Villa Morena has 611.
You already saw on the denominator page that a count tells you where things happen, not how common they are. Now it's your turn to make the fair comparison.
Check yourself: Ciudad Ceiba: 2,272 thefts and 1,420,000 inhabitants. Villa Morena: 611 thefts and 248,000 inhabitants. Where is a theft from a business more common, relative to its population?
A rate is a count divided by who it could happen to
A rate answers "out of every so many, how many did it happen to?" You calculate it in two steps:
- Divide the cases by the population: 611 ÷ 248,000 = 0.002464.
- Multiply by a scale that gives readable numbers: 0.002464 × 100,000 = 246.4 thefts per 100,000 inhabitants.
The second step doesn't change anything underneath. "0.002464 thefts per inhabitant" and "246.4 per 100,000" are the same number; the second one you can read without counting zeros. That's why statistics on uncommon events are given per 100,000 people. INEGI, for example, reported that in 2025 Mexico's rate of presumed homicides was 21.4 per 100,000 inhabitants: 4.7 for women and 38.4 for men (preliminary figures from its press release 42/26, dated August 3, 2026). That last comparison is only possible with rates, because each group is divided by its own population.
If it's not clear why you multiply by 100,000, ask your Maestro.
For more common things you use per 1,000 or per 100 (which is a percentage). You choose the scale; what matters is using the same one for everything you compare, and saying which one it is.
The right denominator
Dividing by inhabitants is an approximation. What can suffer a theft from a business is a business, so the ideal denominator would be the number of businesses in each municipality. With real data, always ask yourself who the event could happen to: accidents per registered car, complications per delivery attended, complaints per receipt issued. If all you have is inhabitants, use them and say so.
For Mexican municipalities, INEGI publishes the population in the 2020 Population and Housing Census, which has tables by state and by municipality. Use the population of the same place as your cases and, if you can, of the same year. INEGI does the same with its own rates: a note in its press release 42/26 explains that for 2020 to 2025 it divides by its estimate of each year's population, as of June 30. If you're unsure how a municipality's official name is spelled, INEGI's catalog lists them all; the 18 in this course are invented and none of them appears there.
Ciudad Ceiba's rate
Worked example · 4 steps
In 2025 there were 2,272 thefts from businesses in Ciudad Ceiba, which has 1,420,000 inhabitants. Calculate its rate per 100,000 inhabitants and compare it with Villa Morena's (246.4).
Work out the next step yourself, then open it to compare.
Look at the two comparisons side by side, for the six municipalities with more than 100,000 inhabitants. On the left, the count; on the right, the rate:
Ciudad Ceiba drops from first place to fourth. Villa Morena, which looked like just another municipality in the counts, is where a business runs the most risk. If management had decided from the chart on the left, it would have avoided the wrong place and opened in the riskiest one.
If you compare places, branches or teams of different sizes at work, ask your Maestro which denominator to use.
Try it
Now calculate the rate for all 18 municipalities. The query below sorts them by number of thefts. Add a tasa_2025 column with the thefts divided by the population, per 100,000, rounded to one decimal place, and sort by that column from highest to lowest. Write 100000.0 with the decimal point: that way the result keeps its decimals.
Return municipio, poblacion, robos2025 and tasa2025 = ROUND(robos2025 100000.0 / poblacion, 1), sorted by tasa2025 from highest to lowest and then by municipio. You're done when you see Ojo de Agua at the top with 285.7, Villa Morena second with 246.4 and Ciudad Ceiba with 160.0.
Your turn
Return municipio, poblacion, robos_2025 and tasa_2025 = ROUND(robos_2025 * 100000.0 / poblacion, 1), sorted by tasa_2025 from highest to lowest and then by municipio. You're done when you see Ojo de Agua at the top with 285.7, Villa Morena second with 246.4 and Ciudad Ceiba with 160.0.
Tables: municipios (municipio, poblacion, robos_2024, robos_2025)
municipios · 18 rows
| Column | Type |
|---|---|
| municipio Nombre del municipio (ficticio). | VARCHAR |
| poblacion Habitantes del municipio. | BIGINT |
| robos_2024 Robos a comercio denunciados en 2024. | BIGINT |
| robos_2025 Robos a comercio denunciados en 2025. | BIGINT |
First rows
| municipio | poblacion | robos_2024 | robos_2025 |
|---|---|---|---|
| Ciudad Ceiba | 1420000 | 2130 | 2272 |
| San Telmo | 612000 | 1040 | 980 |
| Puerto Viejo | 385000 | 480 | 521 |
Every run starts from fresh copies of the course's tables, so try anything. Tab indents; to leave the editor, press Escape, then Tab.
Ready to run your query.
Something odd happened at the top of your table. First place isn't Villa Morena: it's Ojo de Agua, a town of 2,450 people with 7 thefts in the whole year. And near the very bottom is El Encino, another tiny town.
Is Ojo de Agua the most dangerous place in the region to run a business? Hold on to your answer: the next page is about exactly that.