When Luca meets Laura

How to explain important demographic indicators? Try it by telling the story of Laura and Luca. Statistical storytelling at its best!

“From the first breath of life until death, the road of life in Switzerland (and not only here) is strewn with an abundance of data averages from official statistics.
For the past ten years, an average 75,700 babies have been born annually in Switzerland, the majority of whom are boys: 106 boys to 100 girls. His name is Luca. As with most other children, this little boy will grow up in a couple with child(ren), go to school and move on to new horizons. On reaching adolescence he will have to be careful, however. Surveys show that young men aged 15 to 24 years have constituted for a number of years the group at greatest risk of death among persons under 25 years of age. …….
…… Then, around the age of 32, and as for almost two-thirds of Swiss nationals, Luca will join the group of people who have the opportunity to get married, completing the list of 40,700 marriages registered each year in Switzerland. Her name will be Laura. She will be approximately 29 years old when she says “I do” to Luca……..
……… Laura and Luca’s marriage will probably go through some rough times, in particular towards the 6th and 7th year of marriage, a difficult milestone for many couples who often decide to get divorced at this moment. Their marriage will in fact last an average of 15.5 years.” ……………………..
………. Read the full article written by Fabienne Rausa (FSO) here and the magazine ValueS here 


2 thoughts on “When Luca meets Laura

  1. “Their marriage will in fact last an average of 15.5 years.” This claim seems ambiguous. The average length of the first marriage could be among all married couples — or just among those married couples who get divorced. The possessive pronoun in “Their marriage” is ambiguous. “Their marriage” could refer to the preceding “couples who decide to get divorced”; it could refer to all married couples (Laura and Luca?). Odds are the 15.5 years refers to the average length of first marriage among divorced couples. If half of all first marriages end in divorce and if the average length among all couples were 15.5 years, then the average length of marriage among those who never divorced couldn’t be more than 31 years. This maximum average seems shorter than expected for those who marry at age 30 and never divorce. Identifying and eliminating ambiguity in reporting statistics is a major part of statistical literacy.

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